14 Let us, then, hold firmly to the faith we profess. For we have a great High Priest who has gone into the very presence of God—Jesus, the Son of God. 15 Our High Priest is not one who cannot feel sympathy for our weaknesses. On the contrary, we have a High Priest who was tempted in every way that we are, but did not sin. 16 Let us have confidence, then, and approach God's throne, where there is grace. There we will receive mercy and find grace to help us just when we need it.
This scripture is about Christ in his capacity Priest - as opposed to him as a King or a Prophet. It is about him as a religious leader. The head of Christianity.
According to this he knows what it is like to be tempted, as we humans are - as he was tempted by Satan in the wilderness. He knows that it is one heck of a challenge not to be seduced by sin.
Yet he resisted Satan's temptations! - so not only can he relate to us, he can also serve as a good example: a positive role model, who resisted Satan
And finally, it says that God will "help us when we need it" - that if we feel tempted we can pray to Lord Jesus for strength, to help us to successfully resist temptation as he did
Basically, Jesus can share his fortitude with us whenever we pray to him because we are tempted by Satan, or sin. And he will understand what we are going through.