Mosiah 4:21- 4:25
Mosiah 4:21 And now, if God, who has created you, on whom you are dependent for your lives and for all that ye have and are, doth grant unto you whatsoever ye ask that is right, in faith, believing that ye shall receive, O then, how ye ought to impart of the substance that ye have one to another.
So in spite of what we think, our very life is dependent on the good graces of our Heavenly Father. Everything we have is because God has granted them to us. And He gives us whatever we asked that for that is for our own good whenever we ask. So if He is treating us this way, then we should treat those around us in need in the same way.
Mosiah 4:22 And if ye judge the man who putteth up his petition to you for your substance that he perish not, and condemn him, how much more just will be your condemnation for withholding your substance, which doth not belong to you but to God, to whom also your life belongeth; and yet ye put up no petition, nor repent of the thing which thou hast done.
Again if we withhold our help for a man in danger of dying and say his fate is as he deserves, then how much greater will be our condemnation because you are a beggar to God for all that you need to live and move.
Mosiah 4:23 I say unto you, wo be unto that man, for his substance shall perish with him; and now, I say these things unto those who are rich as pertaining to the things of this world.
Therefore a man who treats is fellow unfortunate men in this way shall have a hard time explaining himself at the judgment bar. He will not be able to take them with him into the next world and will end up in the hands of others.
Mosiah 4:24 And again, I say unto the poor, ye who have not and yet have sufficient, that ye remain from day to day; I mean all you who deny the beggar, because ye have not; I would that ye say in your hearts that: I give not because I have not, but if I had I would give.
And to those who just barely making it and have not enough to give to those even less fortunate then themselves but would give if the could, they will be not be held accountable if they cannot give.
Mosiah 4:25 And now, if ye say this in your hearts ye remain guiltless, otherwise ye are condemned; and your condemnation is just for ye covet that which ye have not received.
If this is your true feelings, you will not be held accountable. However, if you do not impart when you can, your condemnation will be just. For that which you have was not yours to start with and you merited nothing. You have what you have by the grace of God and He is seeing if you have the right kind of attitude concerning your substance which is shown by how easily you will give to the poor.