My child,
In Hebrews 6:13, it basically says that when God made a big promise to Abraham, He promised it by Himself because there's no one more powerful than Him. This shows how serious God is about keeping His word. When God promises something, He's super reliable, and this verse proves it.
Now, in Romans 8:28, Paul tells us that nothing at all can separate us from Jesus' love. But what about if we start doubting or losing faith? Well, II Timothy 2:13 tells us that even if we have doubts and turn our back on Jesus, Jesus stays faithful. So, nothing can break the bond between us and Jesus, not even our own doubts.
But wait, if we keep doing wrong stuff, won't Jesus get fed up and leave us behind? Actually, no. Other gods might ditch us for messing up, but Jesus isn't like that. Even when we were at our worst, He still loved us so much that He sacrificed His life for us. What really upsets God is sin, which is why He sent Jesus to wipe our sins away once and for all (Hebrews 10:14).
Love,
Dad