John Gill Commentary Psalms 121:7

"Jehovah will keep thee from all evil; He will keep thy soul." — Psalms 121:7 (ASV)

You Lord shall preserve them from all evil
The Word of the Lord, as the Targum. Not from the evil of affliction, though from that as a penal evil; or as a real one, it being made to work for good: but from the evil of sin; not from the being or commission of it; but from its dominion and damning power, or from a final and total falling away by it.

And from the evil of the world; not from tribulation in it, nor from the reproach or persecution of it; but from the wickedness and lusts that are in it, and from the wicked men of it, their power, rage, and fury: and from the evil one, Satan; not from his temptations, but from sinking under them, and perishing by them; see (John 17:12John 17:15) ;

he shall preserve your soul :
he preserves the bodies of his people, oftentimes from diseases and disasters, and from death, till the appointed time comes; and then he preserves their dust in the grave, and raises it up at the last day; but more especially their souls, the redemption and salvation of which he undertook, and has effected; and which are preserved by him safe to his coming, kingdom, and glory.