What does Psalm 22:15 mean?

Symbolically, David writes about weakness and severe dehydration when his enemies surrounded him—his plight is so traumatic that he feels near death. This continues his dramatic prayer during a time he felt abandoned by God (Psalm 22:1–2), which also serves as a prediction of Messiah's suffering (Matthew 27:46).

A "potsherd" is a fragment of broken clay. The emphasis here is on "dryness," suggesting one whose strength has vanished like the water out of a piece of baked ceramic.

Jesus' strength left Him during the ordeal of His arrest and crucifixion. He was brutalized by Pilate's soldiers. They shoved a crown of thorns onto His head and beat Him with a reed (Matthew 27:27–30). This unusually brutal abuse left Jesus too weak to carry His cross all the way to Calvary. The soldiers compelled Simon, a man of Cyrene, to carry it (Matthew 27:32). In a severely weakened condition on the cross, Jesus died before the two robbers who were crucified alongside Him (John 19:31–33).

Even so, it's worth noting that Jesus died by an act of His will. He called out loudly and dismissed His spirit (Matthew 27:50; Luke 23:46; John 19:30). At one point in His earthly ministry Jesus affirmed: "For this reason the Father loves me, because I lay down my life that I may take it up again. No one takes it from me, but I lay it down of my own accord. I have authority to lay it down, and I have authority to take it up again" (John 10:17–18). It was only after He had fulfilled His mission to provide redemption that Jesus cried, "It is finished" (John 19:30) and dismissed His spirit.