Albert Barnes Commentary Psalms 129:1

"Many a time have they afflicted me from my youth up, Let Israel now say," — Psalms 129:1 (ASV)

Many a time - Margin, as in Hebrew, “much.” Probably, however, the idea is, as expressed in our translation, “many a time;” “often.” So it is in the Latin Vulgate and the Septuagint; and this accords better with the connection.

Have they afflicted me from my youth - Have I been afflicted; have others dealt unjustly by me. The youth here is the beginning of the history of that people: since we began to be a people; since the nation was founded.

May Israel now say - May the nation now say. It is clear from this that the psalm was not written at an early period of their history.