A man can no more take in a supply of grace for the future than he can eat enough today to last him for the next 6 months, nor can he inhale sufficient air into his lungs with one breath to sustain life for a week to come. We are permitted to draw upon God's store of grace from day to day as we need it.
If you really want the good of others, the whole universe may stand against you and cannot hurt you. It must crumble before your power of the Lord Himself in you if you are sincere and really unselfish.