The Shikkerdovid is learning Peah for the shloshim of two people. In chapter 5, the Mishna discuss “Schicha” or “forgetting” some bundles of grain or produce when harvesting. This is left for poor peeople. The introduction or explanation to the this Mishna tell us that this is unique amongst all Mitzvot. According to the introduction mitzvot need “rememberance” or zechira and they quote a pasuk in Devarim. This mitza is unique because it only happens when you forget or unintentionally leave it there. THe mitzva is inadvertent or by chance. The introduction gives a story of a righteous person who goes so far as to give a korban in thanksgiving that he was able to fulfill a mitzva without thinking about it.
The Shikkerdovid would like to flush this out. We like to think we are in control. We like to think that we do good and we get rewarded. The truth is that everything is in Hashems’s hands. Maybe even our mitzvot. If we are lucky to be put in a position to do something good or positive, that we execute properly. Maybe the only thing we really control is that when Hashem puts us in a position to do something good, we are ready and of the right frame of mind that it takes place…even if we dont realize it. The mitzva comes to us… lets be ready.