Charles Ellicott Commentary Psalms 71:20

"Thou, who hast showed us many and sore troubles, Wilt quicken us again, And wilt bring us up again from the depths of the earth." — Psalms 71:20 (ASV)

Quicken me. —According to the written text, quicken us, an indication that the psalm is a hymn for congregational use. As for the change from singular to plural, that is common enough.

Depths ... —Abysses, properly of water. . Perhaps here with thought of the waters on which the earth was supposed to rest. If so, the image is the common one of a “sea of trouble.”