The purpose of our growing in union with God, becoming more holy, is never, never, just for ourselves, that we may grow in sanctity…. The final purpose is that we become more holy, and united with God, that we may be more effective channels of His grace to others. This is the purpose of becoming holy. This is the fundamental motive for growing in sanctity. Why? So, that being united with God ourselves, we might then be used by God, in the measure of our union with Him.
Holy people are used by God to sanctify others,
humble people to bring humility to others, patient people to bring patience, chaste people to bring chastity. (Fr John Hardon, S.J.)