The wisdom behind fasting three days of every month

Question:
And walking is not a means of earning from fasting the days of the monastery, and why did the Lawgiver make them horses?

Answer:
Because one good deed is rewarded ten times over, so if one fasts three days of the month, it is as if he fasted the entire month. One good deed is rewarded ten times over, and the three days can be at the beginning of the month, the middle of the month, or the end of the month, but they say that it is better to fast on the white days, the middle of the month is better, yes.