What does Psalm 8:5 mean?

In this verse David reflects on God's creation of man. He views man as having been created a little lower than the heavenly beings, the angels. Hebrews 2:9 applies Psalm 8:5 to Jesus. Although He created the heavenly beings, Jesus chose to become a man in order to die in the place of sinful man. None of the angels could serve as our substitute and die in our place. Angels do not experience humanity, but Jesus did. Angels are not human, but Jesus lived as a man. Only by becoming human could He serve as a sacrifice for humanity (Hebrews 2:11).

By willingly terminating His life on the cross Jesus paid the penalty for the sins of all who put their faith in Him, past, present, and future. On the cross, Jesus cried out, "It is finished" (John 19:30). The Greek for this expression is tetelestai, meaning, "it stands finished," or "it is paid." Jesus' substitutionary death was sufficient payment for all time for the sins of humanity. Our salvation could not be purchased for anything less than Jesus' blood, and nothing more than His blood is required (1 Peter 1:18–19).