What is the difference between the error of a scholar who is paid for it and Bid‘ah (innovation in religion)? And does the ruling on an ordinary person who falls into Bid‘ah due to a fatwa from a scholar he trusts differ from that on others among Ahl Al-Sunnah (the Sunnis)?

There is no difference between the error of a diligent scholar in subsidiary matters or in judging acts of worship if he is qualified for ijtihad (independent reasoning), and there is no ijma' (consensus) or decisive text on the issue; in such a case, he receives a reward for his ijtihad. A distinction must be made between innovations (bid'ah) whose general category is legislated (like some types of prayers), where the one who errs is excused and rewarded for the legislated part of his worship, and innovations whose general category is not legislated (like shirk (polytheism) or circumambulating graves); these are not a basis for reward at all.

The mujtahid who errs is rewarded for his ijtihad and his good intention, whereas one who does not know the truth and does not strive to know it may sin. The lay follower (ammi muqallid) is not excused for innovation if he falls short in seeking the truth or follows his whims, whereas the diligent scholar who exerts his utmost effort and fears Allah may be rewarded for his ijtihad even if he errs.