 You can only confess that which you have secured in your heart. If you do not have the assurance of who you are in your heart, you will not be able to confess who you are in Christ. Psalm 78, 37 tells us the importance of being steadfast in our heart. Without being steadfast, you will not have the assurance and will not be faithful in the promise that God has given you. You will not trust and be able to act upon what God says.