A.T. Robertson Commentary Hebrews 4:15

"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." — Hebrews 4:15 (ASV)

That cannot be touched with the feeling (μη δυναμενον συνπαθησα). "Not able to sympathize with." First aorist passive infinitive of συνπαθεω, late compound verb from the late adjective συνπαθος (Romans 12:15), both from συνπασχω, to suffer with (1 Corinthians 12:26; Romans 8:17), occurring in Aristotle and Plutarch, in N.T. only in Hebrews .

One that hath been tempted (πεπειρασμενον). Perfect passive participle of πειραζω, as already shown in 2:17f.

Without sin (χωρις αμαρτιας). This is the outstanding difference that must never be overlooked in considering the actual humanity of Jesus. He did not yield to sin. But more than this is true. There was no latent sin in Jesus to be stirred by temptation and no habits of sin to be overcome. But he did have "weaknesses" (ασθενεια) common to our human nature (hunger, thirst, weariness, etc.). Satan used his strongest weapons against Jesus, did it repeatedly, and failed. Jesus remained "undefiled" (αμιαντος) in a world of sin (John 8:46). This is our ground of hope, the sinlessness of Jesus and his real sympathy.