“Be careful not to do your ‘acts of righteousness’ before men, to be seen by them. If you do, you will have no reward from your Father in heaven.
“So when you give to the needy, do not announce it with trumpets, as the hypocrites do in the synagogues and on the streets, to be honored by men. I tell you the truth, they have received their reward in full. But when you give to the needy, do not let your left hand know what your right hand is doing, so that your giving may be in secret. Then your Father, who sees what is done in secret, will reward you.”
— Matthew 6.1-4
“There are many things done by man which are noble in themselves but still because of some reason are not noble. For example, fasts and vigils, prayer and psalmody, almsgiving and hospitality are noble in themselves, but when they are done out of vainglory they are no longer noble.
“God searches the intention of everything that we do, whether we do it for him or for any other motive.
“When you hear the Scripture saying, ‘You will render to each one according to his works,’ know that God will reward good works but not those done apart from a right intention. For God’s judgment looks not on what is done but to the intention behind it.”
— Maximus the Confessor, The Four Hundred Chapters on Love 2.35-37