A priest makes four specific promises, each of which entails certain sacrifices.
Priests in the Roman Rite promise to be celibate, willingly sacrificing the natural gifts of marriage and children. Read more about celibacy.
Priests promise to live simply, giving up lucrative careers and possessions, and instead focusing on serving God’s people.
Priests promise to obey the bishop and his successors, sacrificing their self-determination. They do this for the good of the local Church, moving to where the bishop assigns them.
Priests promise to pray the Liturgy of the Hours at certain times of the day, sacrificing their time to spend time with the Lord.