Bede : Now the word of the Lord came to Samuel, saying, etc. The repentance of God is not a disturbance of the mind, which often befalls men as they reconsider the evil they have committed thoughtlessly; rather, it is called a change in passing things, while the immutable divine foresight remains; for just as not repenting signifies unwillingness to change what has been established. The Lord has sworn and will not repent: You are a priest forever (Psalms 109); this means that what He has once established, He has never changed the priesthood of Christ. However, Saul repented of having been made king; because even the treachery of the entire people of Judea and the false faith of Christians deprives him of the promise of the kingdom's favor. — Commentary on Samuel