The apostle Paul in Romans chapter 11 has an answer for those who says; once saved, forever saved. The logic simply stated says that once a person gives their lives to Christ, they cannot lose it. They take it further and say, the person cannot lose their salvation even if they deny Christ and live however they want. Paul's answer is;
Notice how God is both kind and severe. He is severe toward those who disobeyed, but kind to you if you continue to trust in his kindness. But if you stop trusting, you also will be cut off. And if the people of Israel turn from their unbelief, they will be grafted in again, for God has the power to graft them back into the tree. You, by nature, were a branch cut from a wild olive tree. So if God was willing to do something contrary to nature by grafting you into his cultivated tree, he will be far more eager to graft the original branches back into the tree where they belong.
Romans 11:22-24 NLT.
Israel lost God because they stopped believing in him and were then cut off. Paul is warning us, if he cut them off because of their rebellion and idolatry, they even chose other gods to lead them. Paul says we would experience the same if we fall into the same error.
The Lord will never forsake those who put their trust in him, as long as we are holding on to God and our faith is in him, we can be sure that he would save us.
