What is the ruling on praying behind an Imam whose recitation contains errors to the extent that it deviates from proper tajwid, such as extending a natural madd for more than two harakat, not differentiating between types of mudood and idgham, and altering the meanings of words by substituting letters?

Lahn (mistake in recitation) in prayer is of two types:

1. In Al-Fatiha: If it changes the meaning (such as pronouncing the 'ta' in "an'amta" with a kasra instead of a fat-ha): The prayer becomes invalid, and the imamate of one who does this is not valid. If it does not change the meaning (such as pronouncing the 'dal' in "Al-Hamdu" with a kasra or fat-ha instead of a dhamma): The prayer does not become invalid, but the imamate of one who does this is disliked, and he should be replaced.

2. In other than Al-Fatiha: It does not invalidate the prayer even if it changes the meaning, unless it is done intentionally.

One who makes lahn should not lead the prayer, based on the Prophet's (peace be upon him) saying: "The people are led in prayer by the one among them who is most skilled in reciting the Book of Allah." Jurists have stipulated that the imamate of one who makes lahn is disliked.