Albert Barnes Commentary Psalms 29:4

"The voice of Jehovah is powerful; The voice of Jehovah is full of majesty." — Psalms 29:4 (ASV)

The voice of the Lord is powerful - Margin, as in Hebrew: “in power.” That is, is mighty; or, has strength. Allusion may be made to what seems to be the effect of thunder in prostrating trees, or tearing off their limbs, or it may be merely to the loud sound of the thunder.

Is full of majesty - Margin, as in Hebrew, “in majesty.” That is, it is grand, sublime, overpowering.