Deuteronomy 4:31 (For the LORD thy God is a merciful God;) he will not forsake thee, neither destroy thee, nor forget the covenant of thy fathers which he sware unto them.
We need to be continuously reminded that He is a merciful God. That is repeated all through the Scriptures. Also, He never abandons His people. I suppose the reason these things need to be repeated so much is our insecurities and tendency to think that He is harsh, angry, cruel and will not keep His Word. God promised not to destroy His people. He would not forget what He promised them.
This promise was all written to the Jewish people, not us, not the church. But if God is all that He promised in these verses, then that is what He is. That is His character. We know that He never changes. So that means we can trust Him to be the same way today and with us.
Trust God. Read the Scriptures to know who He is talking to and how it applies to you.