Psalm 64:5-7

Amplified Bible

⁵ 
They encourage themselves in [their pursuit of] an evil agenda;
They talk of laying snares secretly;
They say, “Who will discover us?”
⁶ 
They devise acts of injustice, saying,
“We are ready with a well-conceived plan.”
For the inward thought and the heart of a man are deep (mysterious, unsearchable).