Past Prayer
There is a clear halachah in Shulchan Aruch (230:1) that a prayer on the past is a wasted prayer. The two examples offered are based on a Mishnah and Gemara in Berachos.
Tefillah
Why a prayer asking to change something that has already happened is considered a wasted prayer, with common examples.
There is a clear halachah in Shulchan Aruch (230:1) that a prayer on the past is a wasted prayer. The two examples offered are based on a Mishnah and Gemara in Berachos.