The difference between confidence and arrogance in Scripture is the object. Proverbs 3:26 says "the LORD shall be thy confidence" — the word is kesēl, which elsewhere means folly or self-reliance when pointed at the wrong thing. Confidence directed at yourself is folly; confidence directed at God is wisdom. Same energy, opposite outcomes. The posture doesn't change; the object does everything.
Paul captures this precisely in Philippians 1:6: "being confident of this very thing, that he which hath begun a good work in you will perform it until the day of Jesus Christ." The confidence isn't in your consistency. It's in his faithfulness to finish what he started. That reframes the entire question of assurance — you're not trusting yourself to keep going; you're trusting the one who began to complete.
The Charismatic tradition has a specific emphasis here: the Holy Spirit is the earnest, the down payment, the guarantee of your inheritance. Ephesians 1:13–14 describes the Spirit as a seal and a pledge. Your confidence is not just intellectual — it has a spiritual signature on it. The Spirit's presence inside you is God's own confirmation that the transaction is real and irreversible.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.