And he set up an altar there and called it “God, the God of Israel.” – Genesis 33:20

Sometimes when a kidnapper takes a person as his hostage the police (or family) will demand “proof of life” before a ransom is paid (or any action is taken). This “proof of life” is some sort of objective evidence that the person is still living.
After Jacob (Israel) returned to Canaan he built an altar and called it, “God, the God of Israel.” By his actions (which included the erection of this altar), we see that his life had indeed changed at Peniel. God (of Abraham) was now the God of Israel; his past, his present, and his future … and literally-speaking, “Jacob” was no more.
What is your “proof of life?” That is to say, proof of your new life in Christ? What altars have you built? Is there any objective evidence? Does God truly possess your past, present, and future? Your family, business, and recreation? Your mind, will, and emotion? Does your life bear the marks of His presence … love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control?
Where is the proof of life, the proof of “His life,” in you?