Jesus and Paul taught that God can leave us
Jesus said that the father doesn't leave him because he does all that pleases him. So if we don't do what pleases God, then God can leave us
John 8
And he that sent me is with me: the Father hath not left me alone; for I do always those things that please him.*
And yes we can be cut off again
Romans 11
And if some of the branches be broken off, and thou, being a wild olive tree, wert graffed in among them, and with them partakest of the root and fatness of the olive tree;*Boast not against the branches. But if thou boast, thou bearest not the root, but the root thee.*Thou wilt say then, The branches were broken off, that I might be graffed in.*Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear: For if God spared not the natural branches,*take heed*lest he also spare not thee.*Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, IF thou continue in*his goodness: otherwise thou also shalt be cut off.*And they also, if they abide not still in unbelief, shall be grafted in: for God is able to graff them in again
Matthew 7
Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.*Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.
Romans 6
For sin shall not have dominion over you: for ye are not under the law, but under grace. What then? shall we sin, because we are not under the law, but under grace? God forbid. Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin unto death, or of obedience unto righteousness?
Once saved always saved is a false doctrine and a false security! God doesn't change, he's the same God as in the old testament. If we live a life of sin and turn from him, then he will turn from us, we're only sealed by the holy spirit if we obey God, if not then he will leave us, we can't carry on sinning and expect just to walk into heaven. If we say that were saved and that were sealed by the holy spirit, then we shouldn't be wilfully sinning, we should be walking away from sin and denying ourselves. If we're not, and we're still living our lives by the will of the flesh and this world, then we're not saved in any way. If Christ is within us and we are being led by the holy spirit, then we will be obeying God and living to please him and do his will and not living by the will of the flesh and sin.
You need to take notes and catch up.