What is the ruling on congregational prayer led by a person who replaces the letter "rā’" with a "wāw," while the congregants are unaware of the invalidity of the lisping imam's leadership? And what is the ruling on the imam's own prayer, and is he sinful for his ignorance? And what is the ruling on the lisping imam leading someone who is also lisping, but with a different letter of substitution or type of lisp?

Scholars have differed regarding the imamate of a lisping person (althagh) leading one who is more eloquent than him. The preponderant opinion is that it is not valid unless the congregant is similar to him (in lisping), and this is the view of the majority of scholars. Some have gone to the extent of excusing it due to ignorance. The more cautious approach is to repeat the prayer, and there is no sin upon the imam who invalidated the prayer out of ignorance. As for his (the imam's) own prayer, it is invalidated if there is no one among the congregants who is fit to lead him. However, if there is someone among them who is similar to him (in lisping), then his prayer is valid. You are not obliged to ask the congregants to repeat the prayer because the issue is one of scholarly difference. Scholars have differed concerning the meaning of "similarity" in the imamate of a lisping person by one similar to him: is it only in the letter that cannot be pronounced, or does it also include substitution (of letters)? Since the matter has already occurred, we do not oblige you to repeat it, but we advise you to take this into consideration in the future.