Every word after, if, is predicated upon that word. It means, a proposal, a situation, an example. It says this...IF someone falls away for them to come back it would be putting Christ back on the cross.
You cannot put Christ back on the cross, so, the if means, what follows if, is an impossibility.
To come back would be putting Christ back on the cross...ok. Since we all know the parable of the prodigal son, and he did indeed come back, and Christ cannot be put back on the cross....that means the prodigal son, was, saved and further more, did not lose his salvation. He just got a little confused, and then came back.
You cannot lose something you never earned or achieved ( Romans 9:16 ) and since salvation is of God, and God does not make mistakes, you cannot lose your salvation.
What a fearful place it must be to think you can mess up, or even worse, choose, to lose your salvation...and we all know there is no fear in Christ Jesus.
This is the problem with free will salvation. Since you believe its up to you, in whatever degree your doctrine dictates, then the ability to keep it, must also depend upon you....ya know the same you that did all those sinful things before salvation. The same you the bible says your righteousness is filthy rags. The same you that was dead in your transgressions...the deceitful heart you had...
and you want to trust your ability to choose God? Your vaunted will power to keep your salvation...to manifest works within yourself...to be the ''good'' christian and choose to obey God?
You couldn't do it. Neither could I, nor can I now.
God is God, all praise and honor are His. All glory for salvation is His..all of it. God is the source of..all...good things. God prepares good things for you to do.
Romans 9
Ephesians 2:8-10
Romans 8:28-30
This scripture defines your will.....to die to self so Christ lives in you.