Charles Ellicott Commentary 1 Chronicles 22:11

"Now, my son, Jehovah be with thee; and prosper thou, and build the house of Jehovah thy God, as he hath spoken concerning thee." — 1 Chronicles 22:11 (ASV)

The Lord be with thee. —See 1 Chronicles 9:20. (1 Samuel 3:19; 2 Kings 18:7: The Lord was with him.) The phrase is the origin of the familiar liturgical formula, “The Lord be with you.”

And prosper thou, and build the house. —Not a command, but a wish, i.e., may you prosper and build. The verb “prosper” (literally, carry through, make succeed) is used transitively in 2 Chronicles 7:11 and Genesis 24:40.

As he hath said of (upon) thee. —This phrase (dibbèr ‘al) is specially used of Divine threats and promises. (Isaiah 37:22; and compare to 1 Chronicles 22:8, above: And the word of the Lord became upon me.)