The word infirmity in the Old Testament was connected to the Sanctuary sacrifices, meaning primarily a physical spot or blemish. The animal or priest that had an infirmity, was disqualified from being a sacrifice or from performing in the Sanctuary. (Lev. 1:2,3,10; Lev. 21:16-24). All pointed to Jesus.

In the New Testament the word infirmity (astheneia) is used more to describe a mental, moral and emotional weakness, lack of strength rather than physical defects. Infirmities are not a sin in themselves, but undermine our resistance to temptation.
Since the Old Testament priest had astheneia, inner weaknesses, imperfections, he had to offer sacrifices for himself (Heb. 9:7) so he could understand, be compassionate and gentle in dealing with his people..
Paul applies this picture to our High Priest Jesus Christ. Jesus never sinned (Heb. 4:15), He never yielded to temptation, but He was tempted in every point, as we are. This is why He understands and sympathizes with the feelings of our infirmities.

What are some of the Feelings that Our Lord Jesus understands?
1. He understands the feelings of depression, Matt. 26:37,38
2. He understands the feeling of being forsaken, Matt. 26:40-45; 27:46
3. He understands the feelings of loneliness, Matt 26:56
4. He understands the feeling of being falsely accused, Matt 26:60
5. He understands the feeling of being beaten, struck on the head and face, Luke 22:63,64; Matt. 27:30
6. He understands the feelings of being mocked, scoffed on the cross Matt27:40
7. He understands the feelings of rejection, Matt 27:38-44
8. He was a Man of sorrows and acquainted with grief, Is. 52:2,3
9. He understands to be in Hades= grave Acts 2:27. Meaning that Jesus entered into every fear, anxious feelings that we can experience in our lowest moments of rejection and depression.

Joni Eareckson experience

Jesus walked this lonesome valley,
He had to walk it by Himself;
O nobody else could walk it for Him,
He had to walk it by Himself.

You must go and stand your trial,
You have to stand it by yourself;
O nobody else can stand for you,
You have to stand it by yourself

As we walk our lonesome valley,
We do not walk it by ourselves;
For God sent his Son to walk it with us,
We do not walk it by ourselves

Yes, Jesus died for our sins, but more yet I praise God that Jesus not only knows the facts of our infirmities but He also understand, experienced the feelings of our infirmities!

Invitation: "Let us therefore come (confidently) boldly to the throne of grace, that we may obtain mercy (healing) and find grace to help in time of need.

Why? Because Jesus, who not only bore our sins but also experienced our deepest feelings, can counsel, treat, cure and heal us gently with compassion our infirmities.