Is it possible to combine da’wah with seeking knowledge?

Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allaah
have mercy on him) was asked this question and he answered as follows: 

Undoubtedly calling people to Allaah is something which
has a high status and is very important, because this is the mission
of the Messengers (may the blessings and peace of Allaah be upon them). 
Allaah says (interpretation of the meaning): 

“And who is better in speech than he who [says: ‘My
Lord is Allaah (believes in His Oneness),’ and then stands firm (acts
upon His Order), and] invites (men) to Allaah’s (Islamic Monotheism),
and does righteous deeds, and says: ‘I am one of the Muslims’”

[Fussilat 41:33]

Allaah commanded His Prophet Muhammad

(peace and blessings of Allaah be upon him) to say (interpretation of
the meaning): 

“This is my way; I invite unto Allaah (i.e. to the
Oneness of Allaah — Islamic Monotheism) with sure knowledge, I and whosoever
follows me (also must invite others to Allaah, i.e. to the Oneness of
Allaah — Islamic Monotheism with sure knowledge)”[Yoosuf 12:108]

Of course it is not possible to call people to Allaah
without any knowledge, as Allaah says here, “with sure knowledge”.
How can a person call others to something of which he has no knowledge?
Whoever calls people to Allaah without knowledge is saying things about
Allaah which he does not know. Knowledge is the first step towards da’wah. 

But it is possible to combine knowledge and da’wah from
beginning to end. If you cannot combine them, then you should start
with (seeking) knowledge, because that is the basis on which da’wah
rests. Al-Bukhaari (may Allaah have mercy on him) said in his Saheeh,
in the tenth chapter of Kitaab al-‘Ilm (the Book of Knowledge),
Baab al-‘Ilm qabla al-Qawl wa’l-‘Aml (Chapter on (acquiring)
knowledge before speaking or acting). He quoted as evidence for that
the aayah in which Allaah says (interpretation of the meaning): 

“So know (O Muhammad) that Laa ilaaha illallaah (none
has the right to be worshipped but Allaah), and ask forgiveness for
your sin, and also for (the sin of) believing men and believing women.
And Allaah knows well your moving about, and your place of rest (in
your homes)”[Muhammad 47:19]

He said: so start with knowledge. 

Whoever thinks that he cannot combine (seeking) knowledge
and da’wah is mistaken, because a person can be learning and can also
call his family, neighbours and the people in his town to Allaah whilst
he is still learning. 

People nowadays are in need – indeed it is essential
– of deeply rooted knowledge that will be established in their hearts,
based on the sources of sharee’ah. With regard to the superficial knowledge
by which a person knows just a little about the issues that he comes
across, as the common people know, without any knowledge of its principles
or what it is based upon, this is very limited knowledge which does
not enable a person to defend the truth at a time of necessity in the
face of the arguments posed by those who propagate falsehood. 

What I advise the Muslim youth to do is to concentrate
their efforts on seeking knowledge whilst also calling people to Allaah
as much as they can and in a manner that will not prevent them from
seeking knowledge, because seeking knowledge is jihad for the sake of
Allaah. Hence the scholars said that if a person who is able to earn
a living is kept from doing so by his pursuit of knowledge, he should
be given zakaah, because that is a kind of jihad for the sake of Allaah,
unlike one who does not work in order to concentrate on worship, who
should not be given zakaah because he is able to work.