Can he
    call non-Muslims to Islam with the little knowledge that he has?
Question

                Assalam u alaikum. Is it allowed for
      someone with little knowledge of Islam to inform other people about Islam - just the
      basics i.e. the five pillars and a few brief points on Islam, directing them to more
      knowledable sources for further discussion e.g. websites. Or am I doing an injustice to
      these people? By only giveing them a brief intro and leaving them as they are? For I read
      that everyone will see Islam at some point in their life. That being the case, if I only
      give someone a brief intro would it be okay?
Praise be to Allah.There is nothing at all wrong with conveying what you know of the
    religion of Allaah to non-Muslims, as long as you are certain that it is correct, such as
    the basics that you mention, like the five pillars of Islam or the pillars of eemaan
    (faith). Indeed, this is probably obligatory upon you, as Allaah says (interpretation of
    the meaning): “Let there arise out of you a group of people inviting to all that
    is good (Islam), enjoining al-ma’roof (i.e., Islamic monotheism and all that Islam
    orders one to do) and forbidding al-munkar (polytheism and disbelief and all that Islam
    has forbidden). And it is they who are the successful.” [Aal ‘Imraan 3:104]
The Prophet 
 (peace and blessings of Allaah be upon him) said:
    “Convey from me, even an aayah.” (Reported by al-Bukhaari). Ibn Hajar (may
    Allaah have mercy on him) said: He said in the hadeeth, “even an aayah”, meaning
    one aayah, as if he was saying that every listener should hasten to convey whatever aayaat
    he heard, even if it is only a few. Some of the Sahaabah set out to call their tribes to
    Islam when they had only a little knowledge that they had gained during the brief time
    they had sat with the Prophet 
 (peace and blessings of Allaah be upon him). But even
    though their knowledge was so little, it was correct and was blessed, and because of their
    sincerity, Allaah benefitted others through it. Al-Tufayl ibn ‘Umar went from Makkah
    to his people Daws with the limited amount of knowledge that he had, then he came to the
    Prophet 
 (peace and blessings of Allaah be upon him) in Madeenah accompanied by eighty
    families of Daws, all of whom had become Muslim, and among whom was Abu Hurayrah (may
    Allaah be pleased with him).
Know that some non-Muslims may become Muslim for the slightest reason
    and by hearing the briefest word said to them. Do not think that the knowledge you have is
    too little for the purposes of conveying the Message. “… invite them to your
    Lord. Verily! You indeed are on the (true) straight guidance.” [al-Hajj 22:67 –
    interpretation of the meaning].