Verses 1-3
Psalm 126:1-6. To praise for God‘s favor to His people is added a prayer for its continued manifestation.
When the Lord, etc. — The joy of those returned from Babylon was ecstatic, and elicited the admiration even of the heathen, as illustrating God‘s great power and goodness.
turned again the captivity — that is, restored from it (Job 39:12; Psalm 14:7; Proverbs 12:14). Hengstenberg translates: “When the Lord turned Himself to the turning of Zion” (see Margin), God returns to His people when they return to Him (Deuteronomy 30:2, Deuteronomy 30:3).
Verse 4
All did not return at once; hence the prayer for repeated favors.
as the streams in the south — or, the torrents in the desert south of Judea, dependent on rain (Joshua 15:9), reappearing after dry seasons (compare Job 6:15; Psalm 68:9). The point of comparison is joy at the reappearing of what has been so painfully missed.
Verse 5-6
As in husbandry the sower may cast his seed in a dry and parched soil with desponding fears, so those shall reap abundant fruit who toil in tears with the prayer of faith. (Compare the history, Ezra 6:16, Ezra 6:22).
Verse 6
He that goeth forth — literally, better, “He goes - he comes, he comes,” etc. The repetition implies there is no end of weeping here, as there shall be no end of joy hereafter (Isaiah 35:10).
precious seed — rather, seed to be drawn from the seed box for sowing; literally, “seed-draught.” Compare on this Psalm, Jeremiah 31:9, etc.