This verse shows who is worthy of our trust: the God of Jacob. You are blessed when you trust in him. From the life of the patriarch, Jacob, we see how much the Lord is worthy of that trust! Starting with Jacob’s dream, as written in Genesis 28:10–22: in that dream, the Lord gave promises which he keeps and that is why this God is worthy of (our) trust.
When we read the phrase the God of Jacob,
then two more things are important. First, God had begun a relationship with Jacob, and despite the fact that Jacob often acted manipulative, God stuck to that relationship. We can completely rely on God, even though our responses to him are usually very weak and shaky. Second, the Lord had also given promises regarding Jacob’s offspring (see e.g., Genesis 28:13–14). Though Jacob was the last of the three patriarchs, he was the first with a large family. He had twelve sons and a daughter. God’s promises also apply to them and their children, and to those who, by faith in Jesus Christ, may be counted as the offspring of Jacob.
Psalm 146:5b makes the relationship with God personal by speaking about “hope in his God.”
5 Blessed is he whose help is the God of Jacob, whose hope is in the LORD his God,