שִׁ֥יר הַֽמַּעֲל֑וֹת מִמַּעֲמַקִּ֖ים קְרָאתִ֣יךָ יְהוָֽה׃
A Song of Ascents. Out of the depths have I called Thee, O LORD.
Ibn Ezra on Psalms
Why does it say "from the depth"? Because of the depth of poverty and low status in the diaspora.
שִׁ֥יר הַֽמַּעֲל֑וֹת מִמַּעֲמַקִּ֖ים קְרָאתִ֣יךָ יְהוָֽה׃
A Song of Ascents. Out of the depths have I called Thee, O LORD.