"Give to him readily and have no regrets when you do so, for in return the LORD your God will bless you…" I will interpret this according to what they said in the first chapter of Tractate Hagigah p.5b, in reference to the verse 'For G-d shall bring every work into the judgment concerning every hidden thing, whether it be good or whether it be evil'. What does 'whether it be good or whether it be evil' mean? Shmuel said: He who provides his charity to the poor in his hour of distress. And RASHI, of blessed memory, interpreted: He who provides – in the usual sense, he who provides charity to the poor in his hour of distress, and not in the hour before his distress, so that the poor person may choose the best moment to purchase his foods at a low cost.
This implies that if one gave before 'his hour of distress', and then the poor person was again in need - in his hour of distress - that he can give him a second time, even in his hour of distress, and not that he provide for the poor person [only] in his hour of distress. This is what is meant by saying: if he already gave – before his hour of distress; 'readily' means to give him once again, in his hour of distress. '…and have no regrets when you do so' – thus refers to the second time, in his hour of distress, 'for in return' that you fulfill giving 'readily', that is, giving twice, 'the LORD your God will bless you'.