24 but because Jesus lives forever, he has a permanent priesthood. 25 Therefore he is able to save completely those who come to God through him, because he always lives to intercede for them.
NIV from www.biblegateway.com
We spend a lot of time worrying about physical needs - such as our house, car, food, finances, and health. All these are important in our life, but one form of assurance supersedes all the others. God desires for us to be confident in Him and in His saving grace. He gives us several reasons to be sure of our eternal security.
Jesus makes a personal promise to all believers: "No one will snatch [you] out of my hand" (John 10:28) - and He does not make promises unless He intends to keep them. To assume that we can take an action that would separate us from the Lord once we have been saved would essentially be calling Him a liar.
The hand of God is used throughout Scripture as a symbol of His strength. Once we have received Christ, we are safely in His palm, and no force or action can remove us. If Satan could snatch us away, either by tempting us into sin or through his own power, it would mean he is stronger than God. We know that isn't true because God is omnipotent (2 Chron. 20:6).
Jesus is our advocate with a holy God who cannot look upon sin. In fact, Hebrews 7:25 tell us that Christ "save [s] forever" because He is available to intercede with God on our behalf. In human terms, Jesus is at the right hand of God as a tangible reminder that our sin debt is paid in full.