Does the garment touching an external impurity invalidate the prayer?
Chapter on Praying with Impurity and Other Matters
Al-Mughni
Book of Prayer
Primary text
If the worshipper's garment touches something impure, such as the garment of a person praying next to them or a wall they are not leaning upon, the prayer is not invalidated by that contact. This is because the impurity is neither touching the worshipper's body nor their covering (garment) directly.
Supporting text
There is a possibility that the prayer is invalidated because the covering is meeting an impurity, similar to if the impurity had fallen directly upon the covering.