Answered by Ustadha Shazia Ahmad
Recently, a brother told me that he was making up missed prayers as he never used to pray, out of laziness. When he subsequently realized the importance of learning to perform prayers from a reliable source of fiqh, he began to read through the Reliance of the Traveller only to discover that he had been doing his wudu incorrectly for the entire duration from when he began to pray. His mistake was that he would wash his arms before his face (which invalidates wudu in the Shafi`i school, but not the Hanafi) Does he need make up all of his prayers again, both the ones he was praying as current ones as well as the make up ones? What should he do so as not to over burden himself?
In the name of Allah, the most Compassionate, the most Merciful.
What you have stated in your question is correct. It is valid in the Hanafi school to wash your arms before your face, but it is not valid in the Shafi`I school.
As such, my suggestion (and the suggestion of other notable scholars) is that for all the times he made wudu that way and prayed, he should consider those prayers valid, since they are valid in one school. That would include all the current prayers he prayed, as well as the make-ups.
However, as from this point forward, if he is a follower of the Shafi`i school, he should not perform the wudu out of order; he must wash his face before his arms. If, from now on, he makes the same mistake again, I suggest that he make up any prayer that he has prayed with the incorrect wudu, for it is invalid in our school, and that invalidates his prayer.
And Allah knows best.
Shazia Ahmad