It's this "KNEW FOR SURE" business that bothers you? I say I understand scripture and you try to prove that I can't?
As a Christian I have faith that I can move mountains...do you want to try me on that one? lol
Don't misunderstand our assurance and faith as being sinfully arrogant. As Christians we come into His presence and before the throne with confidence because He tells us we can.
14Therefore, since we have a great high priest who has gone through the heavens,[e] Jesus the Son of God, let us hold firmly to the faith we profess. 15For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are—yet was without sin. 16Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need. Hebrews 4