Hebrews 4:15

For--the motive to "holding our profession" (Heb 4:14), namely the sympathy and help we may expect from our High Priest. Though "great" (Heb 4:14), He is not above caring for us; nay, as being in all points one with us as to manhood, sin only excepted, He sympathizes with us in every temptation. Though exalted to the highest heavens, He has changed His place, not His nature and office in relation to us, His condition, but not His affection. Compare Mat 26:38, "watch with me": showing His desire in the days of His flesh for the sympathy of those whom He loved: so He now gives His suffering people His sympathy. Compare Aaron, the type, bearing the names of the twelve tribes in the breastplate of judgment on his heart, when he entered into the holy place, for a memorial before the Lord continually (Exo 28:29). cannot be touched with the feeling of--Greek, "cannot sympathize with our infirmities": our weaknesses, physical and moral (not sin, but liability to its assaults). He, though sinless, can sympathize with us sinners; His understanding more acutely perceived the forms of temptation than we who are weak can; His will repelled them as instantaneously as the fire does the drop of water cast into it. He, therefore, experimentally knew what power was needed to overcome temptations. He is capable of sympathizing, for He was at the same time tempted without sin, and yet truly tempted [BENGEL].

— Jamieson-Fausset-Brown Commentary (public domain)