“Again Jesus called out with a loud voice and yielded up his spirit.”
~Matthew 27:50

Jesus struggled to stay alive until all prophecies relating to his earthly life had been fulfilled, including the one in which he would be given vinegar during distress. (Ps. 69:21; John 19:30)
By yielding up his spirit, he willingly let himself expire.
He carried out his commission thoroughly even during the most painful and humiliating moment of his life, until it was time to let go of it.
Sometimes we may want to give up on life when our bodies still have a decent amount of living in them.
Jesus’ example shows me that it’s important to see things through to completion, not losing focus of God’s purpose, even on darker days.