Identified With Us As Humans
Jesus could have decided to be an angel but he decided to become one of us. He has chosen to be identified with us. In the most profound way imaginable, the Son of God identified with us by going through the human birth process in order to be thoroughly unified with us.
For assuredly, he does not give help to angels but to the descendants of Abraham. Therefore, he had to be made like his brethren in all things, that he might become a merciful and faithful high priest in things pertaining to God, to make propitiation for the sins of the people (Heb 2:16-17).
The text says it is perfectly obvious that is what "assuredly" means—that he does not help angels. But he gives help to humans, to the descendants or seed of Abraham. But this is more than help. He became one of us through human birth. He fully identified with us through birth. Then, he became our protector as a merciful and faithful high priest. But his protection went beyond mere physical protection of us. He chose to protect us from our own sins by becoming sin for us.
Out of love and affection, Christ has fully identified with us.