cast the first stone
Verb
Meaning
cast the first stone (third-person singular simple present casts the first stone, present participle casting the first stone, simple past and past participle cast the first stone)
(idiomatic) To act self-righteously in accusing another person, believing oneself to be blameless.
Examples
I had a vague memory of being that ridiculous at one time. Let he who hath never worn parachute pants cast the first stone.
If you can take the hot lead enema, then you can cast the first stone.
I am not saying that Hitler was a choir boy. But I am saying, let him who was innocent in the Second World War cast the first stone.
Let him who is without sin cast the first stone.
Wink at small faults unless you can cast the first stone.
I would also like to quote from JOHN 8:7, “Let him or her who is without sin cast the first stone.”