Is prostration valid if performed upon the hands?
Chapter on the Description of Prayer
Al-Mughni
Book of Prayer
Primary text
If a person prostrates upon his hands, the validity of the prayer is subject to a single narration, which states it is invalid. The rationale is that one is prostrating on a limb designated for prostration, leading to a compounding of prostrations upon itself, which is unlike prostrating on a garment.
Supporting text
The validity hinges upon whether direct contact of the forehead is obligatory. If it is not obligatory, then prostration on the hands is permissible, similar to prostrating on a turban. If it is obligatory, then it is not permissible to avoid compounding the site of prostration upon itself.