Charles Ellicott Commentary Psalms 102:11

"My days are like a shadow that declineth; And I am withered like grass." — Psalms 102:11 (ASV)

A shadow that declines. —Rather, a lengthening shadow, growing longer as the day declines, and therefore soon to vanish altogether. (Compare to Psalm 109:23.)

“And now the sun had stretched out all the hills.”
MILTON: Lycidas,

See also Note, Song of Solomon 2:17.