For because he himself has suffered when tempted, he is able to help those who are being tempted.
And to Hebrews 4:15.
For we do not have a high priest who is unable to sympathize with our weaknesses, but one who in every respect has been tempted as we are, yet without sin.
The Saviour was subjected to both these in as severe a form as was ever presented to people. His sufferings surpassed all others; and the temptations of Satan (see Matthew 4) were presented in the most alluring form in which he could exhibit them. Being "proved" or "tried" in both these respects, he showed that he had a strength of virtue which could bear all that could ever occur to seduce him from attachment to God; and at the same time to make him a perfect model for those who should be tried in the same manner.Barnes Notes explains Hebrews 4:15,
He is able to succour ... - This does not mean that he would not have had "power" to assist others if he had not gone through these sufferings, but that he is now qualified to sympathize with them from the fact that he has endured like trials.
Our High Priest is not cold and unfeeling. That is, we have one who is abundantly qualified to sympathize with us in our afflictions, and to whom, therefore, we may look for aid and support in trials. Had we a high priest who was cold and heartless; who simply performed the external duties of his office without entering into the sympathies of those who came to seek for pardon; who had never experienced any trials, and who felt himself above those who sought his aid, we should necessarily feel disheartened in attempting to overcome our sins, and to live to God. His coldness would repel us; his stateliness would awe us; his distance and reserve would keep us away, and perhaps render us indifferent to all desire to be saved. But tenderness and sympathy attract those who are feeble, and kindness does more than anything else to encourage those who have to encounter difficulties and dangersIn practical terms, Jesus has experienced everything we might feel in our own life. He has experienced temptation, malevolence, malice, ill will, murderous intent, suspicion, fury, hatred, contempt, disgust, resentment, distrust, bitterness, unfriendliness, dislike. Jesus was acquainted with grief, sorrow, suffering, He has been humiliated, despised, mocked, abandoned, rejected, persecuted. He has even been executed.
There is nothing we go through on this earth that Jesus as High Priest cannot pray for in intercession with which He has not already experienced and therefore empathizes to the highest degree. You have a loving Father in heaven who is all-powerful, ready to care for you in ways that are for your good and His glory. Be encouraged He is alive, at the right hand of the Father, attuned to your woes and sympathizes with you in perfect empathy.
What a God we have!