Jesus is fully God; Jesus is fully man. He has great power and can sympathize with us. The Hebrews author would have Christians hold firm to their faith and trust in Him.

The New and Living Way | Episode 10 | Hebrews 4:14-5:4

Having then a great high priest, who hath passed through the heavens, Jesus the Son of God, let us hold fast our confession. For we have not a high priest that cannot be touched with the feeling of our infirmities; but one that hath been in all points tempted like as we are, yet without sin. Let us therefore draw near with boldness unto the throne of grace, that we may receive mercy, and may find grace to help us in time of need.

For every high priest, being taken from among men, is appointed for men in things pertaining to God, that he may offer both gifts and sacrifices for sins: who can bear gently with the ignorant and erring, for that he himself also is compassed with infirmity; and by reason thereof is bound, as for the people, so also for himself, to offer for sins. And no man taketh the honor unto himself, but when he is called of God, even as was Aaron.