Does having only a little knowledge prevent one from reading to people from a book in the mosque?

May Allaah reward you for the efforts you are making to fulfil the duty of
teaching your Muslim brothers. The Prophet
(peace and blessings of Allaah be upon
him) said: Allaah and the angels, and even the ant in its nest and the whale in the
sea will pray for the one who teaches people good things.

(Reported by
al-Tabaraani from Abu Umaamah; see Saheeh al-Jaami, 1838).
Your reading to the people from the books of the scholars is very good for you and for
them, so keep doing that. What we advise is that a person should not speak about things of
which he has no knowledge, either by commenting on the book or by answering questions. If
he does not know something, he should say, Allaah knows best. He should also
avoid speaking about topics he is unsure of, and should stick to things he is certain
about. You are filling an important gap in the Muslim community, and for every good deed
to which you call and guide others sincerely for the sake of Allaah you will
receive a reward for dawah and teaching others, as well as a reward equivalent to
that of those who act upon what they have learned from you, as the Prophet
(peace and
blessings of Allaah be upon him) said: Whoever calls others to right guidance will
have a reward like the rewards of those who follow it, without it detracting in the least
from their rewards. (Reported by Muslim, 4831). Remind your
imaam of his duties as much as you can. We ask Allaah to help us and you to obey Him and
to do that which pleases Him. May Allaah bless our Prophet Muhammad.