John Gill Commentary Psalms 124:2

"If it had not been Jehovah who was on our side, When men rose up against us;" — Psalms 124:2 (ASV)

If [it had not been] the Lord who was on our side
This he repeats both for the confirmation of it, and to excite the attention of the Israelites to it; as well as to observe that it was not once only, but again and again, many times the Lord appeared to be on their side. The Targum renders it, ``the Word of the Lord;'' the essential Word, the Son of God; and so in (Psalms 123:1) , in the king's Bible;

when men rose up against us ;
wicked men; though no hard epithet is given in the text, however just. The enemies of God's people are only called "men" by them, to show their meekness and patience; it is in the singular number, "when man rose up"; hence Aroma interprets it of Pharaoh king of Egypt; and R. Obadiah of Haman: but it might be better interpreted of the man of sin, the man of the earth; who, at the head of his antichristian party, has rose up against the saints, oppressed them, and threatened them with utter ruin, (2 Thessalonians 2:4) (Psalms 10:18) (Revelation 13:5Revelation 13:6) . Though it is best to understand it of a body of men; of men not mean, but mighty; not few, but numerous; and who united as one man against the people of God, and rose up against them in an hostile manner; being full of enmity to them, and bent upon their ruin.