1st: Because He IS God incarnate.
2nd: Because Christ humbled himself and became a man, he had to suffer every temptation like we do. He knows exactly what we are going through (you read this in Phil. 2), he knows our suffering because He has endured it! Since he triumphed over the temptation to sin, he has the authority over sin.
So the next question is: Jesus humbled himself to become fully man, so, being fully man, how did Jesus overcome sin?
1. As a man he had potential to sin. Some people think that it wasn't possible for Jesus to sin. in Latin the term is "Non posse peccare" but that isn't true.. It wasn't impossible for Jesus to sin.. But it is possible for him not to sin. The term is "Posse non peccare".. Meaning that he had potential to sin, but he was able to not sin.. He was able not to sin because he had direct communion with God the Father and was empowered and strengthened.
Now, because of Christ's death, resurrection and ascension we have received God's grace and The Holy Spirit who through God's grace welcomes us into the family.. Into relationship and fellowship with the Father. Through this relationship and community with the Trinity we too are strengthened and empowered by God to fight temptation.
Jesus stands holding our hand and he pulls us into this relationship and he makes it possible.
So, how are we supposed to respond to this?
1. Allow the Holy Spirit to work to empower us.. In John and Acts the Holy Spirit is talked about as a Helper.. He helps us.
2. Trust- Trust that God has given us authority over temptation. Believe it!
3. Act in this belief- Walk in God promise that we will find help to resist temptation... Put on the shoes and walk in them. Start living in a way that suggests that we believe what is written in this passage!
4. Take the practical step of having someone to be accountable with!
That's just how I worked through it.. A person could probably spend many many hours diving into these verses.. They're very rich verses! As is the whole book of Hebrews!