Psalm 52
Against Doeg, whose report led to the slaughter of the priests at Nob (1 Samuel 22). The psalm targets a tongue "like a sharpened razor" and a man who trusted wealth instead of God. Against him David pictures himself as a green olive tree in God's house, rooted in chesed that "endures all day long."
"But I am like an olive tree flourishing in the house of God; I trust in the loving devotion of God forever and ever." (Psalm 52:8)