Deuteronomy 15:15 And thou shalt remember that thou wast a bondman in the land of Egypt, and the LORD thy God redeemed thee: therefore I command thee this thing to day.
Moses is reminding them that God wants them to take care of poor people. He tells them that the poor will always be there but that they are to remember when they were slaved in Egypt.
So there is a great lesson for all of us here. As we prosper more and more we need to be careful not to think that we have down it! We need to remember that God rescued us. We need to put ourselves in their shoes. Be good to them. You, too, have had problems. You, too, have baggage and skeletons in your closet.
Never forget where you came from and that will help you be more grateful to God for all that He has sone and is doing in your life!