All our temptations come from the natural instinct of independent biological organisms to self-optimize; that is, to improve their standard of living, to reproduce, and to take steps to survive (Genesis 3:6, Romans 7:23, James 1:14).
Angels are not biological organisms (in the sense that they are not made of fallible biological material like we are), and have no need to self-optimize. Specifically:
- They have no need to improve their standard of living (they’re in the presence of God which the Bible describes as the optimal standard of living, Revelation 21:3-4);
- They have no need to reproduce (they don’t marry, Mark 12:25, Luke 20:36);
- They have no need take steps to survive (they live forever, Luke 20:36).
They are already superlatively optimized. Therefore they can have free will without being robots, and yet not be tempted as we are. They have one will, to serve their Creator (Psalm 103:20).