The ruling on saying "Grant us rest through it" instead of "Establish the prayer"

Question:
An imam says "Grant us rest through it" instead of "Establish the prayer"?

Answer:
The Prophet (peace and blessings be upon him) said it on some occasions: meaning: when we enter into it, we find rest. It is not "Grant us rest from it," but "Grant us rest through it," for the prayer is a source of comfort.
Q: One finds rest in it?
The Shaykh: The believer finds rest in it.
Q: Does he say it, or is it disapproved of him?
The Shaykh: There is nothing wrong with it. The Prophet (peace and blessings be upon him) said it in some prayers, saying: .