Hebrews 2:15

How is it possible, he is saying, for Christ to style himself our brother or call us really children unless he bears the same nature? Hence on assuming it he overcame the influence of death and did away with the dread besetting us. We lived ever in the dread of death because we were forced to haul the yoke of mortality. Now, it was very necessary for him to use the phrase "likewise" so as to refute the calumny of mere appearance.

"all their lives were held in slavery by their fear of death." — [PHOTIUS] Before, he says, death was abolished, throughout their lives, humans were exposed and subjected to the fear of slavery: for they feared death which had not yet been abolished: and nothing of worldly pleasures could delight the courageous, and this was due to the fear of death, in the manner of a cruel and savage master always pressing and terrifying those who were on the earth. "were held in slavery." The people were bound to death, as they were guilty of this slavery. The slavery of death is to be held and subjected to sin, for sin is the power and sting of death. (1 Cor. 15:56) Therefore, since Christ through death abolished the one who has the power of death, that is,the Devil, the inventor and leader of sin, sin has become weak, and we have been freed from the slavery according to its dominion; we have been liberated from the fear of death. And this is clearly seen in their very actions. For those who before feared and shunned death as the greatest evil and overwhelming, now approach it joyfully as a change of life and a prelude, when they are brought forth for Christ and His laws by those who persecute them. Therefore, is it not evident that the Savior has freed us from the fear of death and from the slavery that comes from it?

"Since therefore the children," summoned through his promise, "share in flesh and blood," that is sin, as signified by flesh, "and he himself likewise partook of the same nature" in the likeness of flesh, he was mingled with them, so that he might become for them a model of goodness. He consigned himself to death, so that through his death "he might destroy him who has the power of death, that is, the devil," who instilled death into living creatures when the fruit was eaten. So he died in order "to free," through his death, those over whom the fear of death ruled and "who were, for all their lives, subject to the slavery of eternal death." You do not receive the medicine that vivifies your life from angels, but from the seed itself of Abraham, to whom it was said, "In your seed all nations will be blessed." "So he had to become similar in everything …" to the children of Abraham, "in order to become as merciful" as Moses, who, as an image of the Son, devoted himself to the salvation of the children of his nation. And [he had to become similar] also in order to become faithful and save all the nations from death, like Aaron, who in the mystery of the Son repelled death from the children of his generation by using the censor, which he received to oppose death. God appointed him high priest not for those things which are generously given to us through sacrifices, as through Eleazar, but for those which are spiritually granted to us in him: that is, in order that he becomes the propitiator through baptism and not through aspersion."Because he himself has suffered and been tempted"—that is, he was tempted through his becoming connatural with us—he is able to assist those who are infirm in their weakness and victims of temptation. In fact, he is now made aware of … the weakness of flesh and knows humans more fully after clothing himself with flesh.