In Luke 6:38, Jesus says, “Give, and it will be given to you. Good measure, pressed down, shaken together, running over, will be put into your lap. For with the measure you use it will be measured back to you.”
Charity – giving to the poor – is an essential part of Christian morality… I do not believe one can settle how much we ought to give. I am afraid the only safe rule is to give more than we can spare. In other words, if our expenditure on comforts, luxuries, amusements, etc., is up to the standard common among those with the same income as our own, we are probably giving away too little. If our charities do not at all pinch or hamper us, I should say they are too small. There ought to be things we should like to do and cannot because our charitable expenditure excludes them.
– C.S. Lewis, (1898-1963), Virtue and Vice