He wants to become Muslim but he works as a tattoo artist

Firstly: 

The greatest blessing that Allah can bestow upon His slave is
to enable him to discover Islam and open his heart to believe in Him and to
submit to Him. Allah, may He be exalted, says (interpretation of the
meaning):

“And whomsoever Allâh wills to
guide, He opens his breast to Islâm, and whomsoever He wills to send astray,
He makes his breast closed and constricted, as if he is climbing up to the
sky. Thus Allâh puts the wrath on those who believe not”

[al-An‘aam 6:125]. 

Shaykh al-Sa‘di (may Allah have mercy on him) said: 

Allah says – explaining to His slaves the sign of a person
being blessed and guided and the sign of a person being doomed and
misguided: if his heart is open to Islam and is filled with the light of
faith and certainty, and he feels at ease with that in himself and he loves
good and does it willingly, and he enjoys it and does not find it
burdensome, this is a sign that Allah has guided him and blessed him by
enabling him to follow the straight path. 

And the sign of the one whom Allah wishes to leave astray is
that he finds his heart constricted and he feels uneasy with ideas of faith,
knowledge and certainty; his heart is immersed in specious arguments and
whims and desires, and no goodness can reach him; his heart is not open to
doing good. In his constriction it is as if he is climbing up to the sky,
i.e., as if he has been made to climb up to the sky, which he is reluctant
to do.  

This reason, the fact that they do not believe, is what
dictated that Allah should put the wrath on them, because they closed the
door of mercy and goodness for themselves. This is a rule that does not
change. The one who gives (in charity) and fears Allah and testifies to the
truth, Allah will show him the path of ease, but whoever is miserly and
thinks he does not need any guidance and disbelieves in the truth, Allah
will show him the path of evil. 

End quote from Tafseer al-Sa‘di, 272. 

We ask Allah to guide you and open your heart to Islam, and
to bless you by enabling you to submit to Him and accept His religion. 

Secondly: 

Your entering Islam is something that is obligatory and there
can be no delay or hesitation, because it is the way to eternal happiness
and salvation from disbelief and eternity in Hellfire. So there is no room
for choice in that regard, and you should not place any obstacle in the way,
no matter what it is. Rather you should hasten to enter Islam straight away,
and throw off the life of heedlessness and confusion. When you do ghusl
(full ablution) and pray and prostrate before Allah, you will realise the
difference between being a person who is a slave to Allah the Almighty
Creator, and being a person who is a slave to his own self and his whims and
desires. 

Perhaps you think now that you will never overcome the haraam
deed that is tattooing, but we believe that when you become Muslim, you will
gain an amazing strength by which you will attain victory over your nafs
(self) and you will find your freedom and pleasure in obeying the command of
your Lord and sacrificing worldly gains and pleasures to please Him. 

Entering into the new religion means that one is breaking
free from constraint, constriction, humiliation and a life of hardship.  

It is freeing one’s soul to soar in a vast world which can
hardly encompass his joy and happiness, and one will be prepared to
sacrifice what is dear and precious in order to retain this happiness. 

Life is filled with dozens and hundreds of stories and cases
in which people — after becoming Muslim — were able to overcome habits and
attitudes that had been deeply rooted in their lives, such as zina
(fornication, adultery) and drinking alcohol; giving up such things is much
harder than giving up a job or profession. 

Islam instils in the hearts of its followers the certainty
that Allah is the Sovereign, the Provider Who provides for His slave from sources they could not imagine, and He does not disappoint anyone who puts his hope in Him.

“And whosoever fears Allaah and keeps his duty to Him, He
will make a way for him to get out (from every difficulty).

3. And He will provide him from (sources) he never could
imagine. And whosoever puts his trust in Allaah, then He will suffice him.
Verily, Allaah will accomplish his purpose. Indeed Allaah has set a measure
for all things”

[al-Talaaq 65:2-3]. 

These are not just words aimed at stirring up emotions;
rather it is truth that one must believe in. Allah is the Creator and
Sovereign of all things, and He has promised His slave that He will provide
for him and suffice him and grant him happiness, if he fears Him and obeys
Him. Allah never breaks His promise and what is beyond His power when He is
Able to do all things? 

Do you think that Allah would grant you provision when you
disbelieve in Him and are disobeying His commands, then when you believe in
Him and make sacrifices for the sake of His religion, He would abandon and
forsake you?? 

O slave of Allah: 

You must have heard of Makkah (Mecca), where our Prophet
Muhammad (blessings and peace of Allah be upon him) was born, to which
pilgrimage is performed to the sacred House of Allah, which is the fifth
pillar of Islam (Hajj = pilgrimage). 

Have you heard of the well of Zamzam from which water springs
in Makkah? 

Do you know the story behind this amazing water, which has
continued flowing for thousands of years until today? 

It is an amazing story, which is like your story to a large
extent. 

The Prophet of Allah Ibraaheem (Abraham — peace be upon
him), took his wife Haajar (Hagar), the mother of Ismaa‘eel (Ishmael —
peace be upon him) to settle her in the place that would become the location
of Makkah (Mecca); it was an uninhabited place at that time, with no
inhabitants, no water, no agriculture, nothing…

… Then Ibraaheem brought Haajar and her son Ismaa’eel when
she was still breastfeeding him, to a place near the Ka’bah under a tree on
the spot of Zamzam, at the highest place in the mosque. During those days
there was nobody in Makkah, nor was there any water. So he left them there
and left with them a leather bag containing some dates, and a small
water-skin containing some water, and set out homeward. Ismaa’eel’s mother
followed him saying, “O Ibraaheem! Where are you going, leaving us in this
valley where there is no person whose company we may enjoy, nor is there
anything (to enjoy)?” She repeated that to him many times, but he did not
look at her. Then she asked him, “Has Allaah commanded you to do this?” He
said, “Yes.” She said, “Then He will not forsake us,” and went back while
Abraham proceeded onwards. When he reached al-Thaniyah where they could not
see him, he turned to face the Ka’bah, and raising both hands, invoked Allah
saying the following prayer:  

“O our Lord! I have made some of my offspring to dwell in
an uncultivable valley by Your Sacred House (the Ka‘bah at Makkah) in order,
O our Lord, that they may perform As-Salaah (Iqaamat-as-Salaah). So fill
some hearts among men with love towards them, and (O Allaah) provide them
with fruits so that they may give thanks”

[Ibraaheem 14:37].

Ismaa’eel’s mother went on breastfeeding Ismaa’eel and
drinking from the water (she had). When the water in the water-skin had all
been used up, she became thirsty and her child also became thirsty. She
started looking at him (i.e. Ismaa’eel) tossing in agony. She left him, for
she could not endure looking at him, and found that the mountain of al-Safa
was the nearest mountain to her on that land. She stood on it and started
looking at the valley keenly so that she might see somebody, but she could
not see anybody. Then she descended from al-Safa and when she reached the
valley, she tucked up her robe and ran in the valley like a person in
distress and trouble, till she crossed the valley and reached al-Marwa where
she stood and started looking, expecting to see somebody, but she could not
see anybody. She repeated that (running between al-Safa and al-Marwa) seven
times.  

Ibn ‘Abbaas said: The Prophet (peace and blessings of Allaah
be upon him) said, “This is the (origin of) the people’s saa’i (walking)
between them between them (i.e. al-Safa and al-Marwa).” When she reached al-Marwa
(for the last time) she heard a voice and she said to herself “Shh!” and
listened attentively. She heard the voice again and said, “O, (whoever you
may be)! You have made me hear your voice; have you got something to help
me?” Then she saw an angel at the place of Zamzam, digging the earth with
his heel (or his wing), until water appeared. She started to make something
like a basin around it, using her hand in this way, and started filling her
water-skin with water with her hands, and the water was flowing out after
she had scooped some of it. 

Ibn ‘Abbaas said: The Prophet (peace and blessings of Allaah
be upon him) said, “May Allah have mercy on the mother of Ismaa’eel! Had she
let Zamzam (flow without trying to control it) (or had she not scooped from
that water) (to fill her water-skin), Zamzam would have been a stream
flowing on the surface of the earth.” And he said: “The angel said to her,
‘Do not be afraid of being neglected, for this is the House of Allah which
will be built by this boy and his father, and Allah never neglects His
people’…” 

The story was narrated at length in Saheeh al-Bukhaari,
3364. 

See how the mother of Ismaa‘eel (peace be upon him) had
certain faith that Allah would not forsake them so long as Ibraaheem did
what Allah commanded him to do. 

Look at the angel who came to her to bring forth water for
her and her thirsty child from the depths of the earth; He said to her: Do
not be afraid of being neglected … 

So do not be afraid of being neglected, for Allah, may He be
glorified and exalted, is too generous and kind for that and He is greater
than you can ever imagine. 

This does not apply only to you; rather this is something
that is repeated with thousands of Muslim people… They are afraid to
repent and follow the path of righteousness because they are working in
haraam jobs, in banks that deal in riba (usury), or in casinos, or in haraam
types of entertainment, and so on. The Shaytaan makes them fear poverty and
makes them think that there is no alternative way of earning a living, as
Allah says (interpretation of the meaning): “Shaitân (Satan) threatens
you with poverty and orders you to commit Fahshâ (evil deeds, illegal sexual
intercourse, sins); whereas Allâh promises you Forgiveness from Himself and
Bounty, and Allâh is All-Sufficient for His creatures’ needs, All-Knower”
[al-Baqarah 2:268]. 

But reality demonstrates that most of those who repent find
that opportunities to earn a halaal income open up for them that they could
never imagine. 

Hence we say: hasten to become Muslim and free yourself from
the shackles of disbelief; remove its darkness from your eyes and save
yourself from the Fire. Do not fear poverty when you are under the
protection of the Lord of the Worlds, the Sovereign Whose stores are never
empty. And be certain that He will never forsake His slaves or abandon His
people and close friends. 

Let us assume, for argument’s sake, that you do not find any
halaal means of earning a living after you become Muslim, so you go back to
your haraam job. What comparison can there be between your situation before
and your situation after? It is a comparison between a believing Muslim who
affirms the oneness of Allah but commits sin, and a person who disbelieves
in Allah. There is no comparison between them at all. The wise man, if he
chooses between two bad things or two evils, will choose the lesser of the
two. So he will not choose a combination of disbelief and sin; rather he
will choose Islam and guidance, and if he falls into sin after he
disciplines himself in obedience to Allah, then in that case he will have
the hope of forgiveness. 

However we say that this is only an assumption; we think that
Allah will honour you, provide for you and bestow upon you from His bounty
that which you cannot imagine, because He is the Most Generous, the Kind,
the Most Merciful Who says (interpretation of the meaning):

“Whoever works righteousness, whether male or female,
while he (or she) is a true believer (of Islâmic Monotheism) verily, to him
We will give a good life (in this world with respect, contentment and lawful
provision), and We shall pay them certainly a reward in proportion to the
best of what they used to do (i.e. Paradise in the Hereafter)”

[al-Nahl 16:97]. 

Finally, the best news you can give us is the news that you
have become Muslim and a believer, and we are waiting for this wonderful
news. 

O Allah, open his heart to faith and guide his heart to
Islam, and bestow upon him the bounty of Your mercy. 

And Allah knows best.