The blow did not come first. The vision did.
"And Mosheh turned, and considered in the wisdom of his mind, and understood that in no generation would there arise a proselyte from that Mizraite man, and that none of his children's children would ever be converted; and he smote the Mizraite, and buried him in the sand."
The Targum Pseudo-Jonathan on Exodus (2:12) gives Moses a terrifying gift: prophetic foreknowledge, exercised in one second, before his fist comes down. He scans the Egyptian's future lineage. No ger. No soul will ever emerge from this man's line that will accept the God of Israel. This is a life that will produce only more cruelty, forever.
Only then does Moses strike.
This is not a rage killing. The Targum is careful to describe it as a judicial act performed by a prophet. Moses is operating like a judge in a heavenly court, seeing the entire future of this soul and concluding that no redemption is possible here — only more harm. He renders the verdict and executes it, and buries the man in the sand, the Aramaic echoing Abraham's own burial of kindness in desert earth.
Medieval commentators were uneasy. Did Moses really have the right? The Targum Pseudo-Jonathan says yes — but only because his insight was prophetic, not personal. The moment Moses leaves the prophetic frame, the next verse will show his mistake. He buries the Egyptian in sand because he thinks the sand will hold a secret. It will not.
Beloved, be slow to strike. The Targum only justifies Moses because he saw the entire future in an instant — and that is a mercy you and I do not have.