Purim is the day we give a donation to whoever asks. Anyone who puts out his hand and requests aid, should be helped, even though we have not checked his bank statement or checked to see that his cause is, in fact, worthwhile.
This also refers to how G-d relates to the Jews on the day of Purim. On Purim, G-d will listen in a special way to our prayers. Even though all year round G-d may only give us what we deserve, on Purim, He is willing to give to us even that which we may not be so deserving of. All we have to do is to put out our hand and ask!!
After all, "Anyone who stretches out his hand should be given to."