It is not the being seen of men that is wrong, but doing these things for the purpose of being seen of men. The problem with the hypocrite is his motivation. He does not want to be holy; he only wants to seem to be holy. He is more concerned with his reputation for righteousness than about actually becoming righteous. The approbation of men matters more to him than the approval of God.
Saint AugustineYou have been professing yourself reluctant to throw off your load of illusion because truth was uncertain. Well, it is certain now, yet the burden still weighs you down, while other people are given wings on freer shoulders, people who have not worn themselves out with research, nor spent a decade and more reflecting on these questions.
Saint AugustineGod suffers not the pain of repentance, nor is He deceived in any matter, so that He would wish to correct that wherein He has erred. But as when a man repents of anything, he wishes to change what he has done; thus where you hear that God repents, look for an actual change. God does it differently from you, although He calls it by the name of repentance; for thou dost it, because you had erred; while He does it, because He avenges, or frees.
Saint Augustine