There are quite a lot of them. I think the predominant ones are in Romans 5 and Romans 8:32. In Romans 5:8, Paul says, “God has demonstrated His love toward us—He has proved His love toward us—in that while we were still sinners, Christ died for us.”
The other that has long been a real go-to passage for me is Romans 8:32. Romans 8:31 asks, “If God is for us, who can be against us?” How do I know God is for us? It’s not because things are going well in my life, because if things start going badly in my life I’ll doubt that God is for me. The answer is that I know God is for me because “He didn’t spare His own Son but gave Him up for us all.” And Paul reasons from that: if He has gone that far for you, His love will never fail you.
I came across a lovely saying a number of years ago from John Donne, the English metaphysical poet, who says, playing off John 13:1, he says that God loves us to the end, to His end, not to our end, and His end is that He might love us more. And I find that beautifully expressed in Romans 8:32. It’s long been an anchor to my soul in times of challenge.