Why is self-trust a problem for Christians?

The Scriptures advise against confidence in the flesh, as articulated in Philippians 3:3. Relying on our own wisdom, intentions, or abilities can result in spiritual blindness and self-deception. In Jeremiah 17:9, it's stated that 'the heart is deceitful above all things,' indicating that our natural inclinations cannot be trusted. Believers are to put their trust in God and His promises, acknowledging that only through His grace can they stand firm in faith. This dependence leads to a genuine understanding of grace and the necessity of Christ's work on our behalf.