What is the ruling on following one madhhab (school of thought) in ritual purity (tahara) and another in prayer (salat)? And does the prayer of one who prays with non-impure blood, according to the madhhab of Ibn 'Uthaymeen, become invalidated if it is considered impure according to the madhhab of Al-Shafi'i?

Whoever is unable to weigh the opinions of the scholars must follow (taqlid) someone whose knowledge and piety he trusts, and he is not obligated to continue following the same person he followed in every issue. Indeed, there is a consensus that whoever embraces Islam is permitted to follow (taqlid) any scholar he wishes. Therefore, there is no impediment to adopting the rulings of purity from one madhhab and prayer from another, unless this is done out of caprice and a pursuit of dispensations without legitimate legal evidence.