Abraham told Abimelech Sarah was his sister, so he’d taken her to be his wife. Before he does anything, God comes to him in a dream to warn him.
God keeps Abimelech from sinning thus resulting in him bringing fear of God to him and his people and providing for Abraham and Sarah.
Reaction: Arose early to obey
"You are a dead man...for the penalty of your sin is death"
God comes and prevents the sin from increasing - he protects Sarah where Abraham should have done, but more than that - Abimelech’s nation now fears God. For God always recieves the glory.
Abimelech is honest to God and God acknowledges Abimelech’s honesty and integrity, but makes it clear it is His doing - “I prevented you from sinning”
Lead me not to sin against you and save me from my faults becoming greater sin. Amen