Romans 11:22-24

22Then appreciate the gracious kindness and the severity of God: to those who fell [into spiritual ruin], severity, but to you, God’s gracious kindness—if you continue in His kindness [by faith and obedience to Him]; otherwise you too will be cut off.

23And even they [the unbelieving Jews], if they do not continue in their unbelief, will be grafted in; for God has the power to graft them in again.

24For if you were cut off from what is by nature a wild olive tree, and against nature were grafted into a cultivated olive tree, how much easier will it be to graft these who are the natural branches back into [the original parent stock of] their own olive tree?