What does the Bible say about boasting in oneself?

The Apostle Paul speaks against the folly of boasting in oneself throughout 2 Corinthians 11. He emphasizes that true authority and legitimacy come from God and not from our personal accomplishments or heritage. Boasting is folly because it contradicts the essence of grace; as stated in Ephesians 2:8-9, salvation is a gift from God, not of works, lest anyone should boast. Therefore, any achievements or spiritual gifts we possess should lead us to humility and gratitude rather than pride.