It is a sin directly against one's neighbour, since one man cannot over-abound in external riches, without another man lacking them.
Thomas AquinasOne aspect of neighbourly love is that we must not merely will our neighbours good, but actually work to bring it about.
Thomas AquinasGive us, O Lord, a steadfast heart, which no unworthy affection may drag downwards; give us an unconquered heart, which no tribulation can wear out; give us an upright heart, which no unworthy purpose may tempt aside. Bestow upon us also, O Lord our God, understanding to know you, diligence to seek you, wisdom to find you, and a faithfulness that may finally embrace you; through Jesus Christ our Lord.
Thomas Aquinas