Ruling on making    bets in matters of shar’i knowledge
Question

Some students of shar’i knowledge make a kind of bet whereby the one who is wrong (on a given issue) has to buy a book, for example, for the one who gets it right. Is this halaal?
Praise be to Allah.This is a competition, and Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) thought that there was nothing wrong with competitions on issue of sharee’ah. He explained this by pointing out that jihaad may be either with knowledge or with weapons. He also used as evidence the reports about Abu Bakr (may Allaah be pleased with him) when the aayah (interpretation of the meaning) “Alif-Laam-Meem. The Romans have been defeated in the nearer land (Syria, Iraq, Jordan and Palestine), and they, after their defeat, will be victorious, within three to nine years…” [al-Room 30:1-4] was revealed. The Persians were the ones who had defeated the Romans; the Romans were Christians, People of the Book, whilst the Persians were Magians (Zoroastrians), who had no revealed Book. Allaah said (interpretation of the meaning): “… And on that day, the believers (i.e., Muslims) will rejoice (at the victory given by Allaah to the Romans against the Persians).” [al-Room 30:4], because the believers wanted the Christians to defeat the Persians as the Christians were People of the Book and therefore closer to Islam than the Magians. Quraysh, on the other hand, wanted the Magians to defeat the Romans, and said, “The Romans cannot defeat the Persians, because the Persians are stronger than they are, and they do not believe in the Qur’aan.” So Abu Bakr bet them a number of camels that (the Romans) would prevail within seven years. The seven years passed and nothing had happened. Abu Bakr (may Allaah be pleased with him) went to the Messenger of Allaah (peace and blessings of Allaah be upon him), who told him, “Add two years, and increase the bet”
(reported by Ibn Jareer in his Tafseer, 10/165, 166, no. 27876) – because the word bid’ used in the aayah refers to any number between three and nine. So the Prophet (peace and blessings of Allaah be upon him) told him to play it safe by increasing the time period and increasing the prize. Abu Bakr did this, and before the two years had passed, travellers brought news that the Romans had defeated the Persians. From this report Shaykh al-Islam deduced that it is permissible to bet in matters of shar’i knowledge.