Titus chapter 2:
11 For the grace of God has appeared for the salvation of all men, 12 training us to renounce ungodliness and worldly passions, and to live sober, upright, and godly lives in this world, 13 awaiting our blessed hope, the appearing of the glory of our great God and Saviour Jesus Christ, 14 who gave himself for us to redeem us from all iniquity and to purify for himself a people of his own who are zealous for good deeds. 15 Declare these things; exhort and reprove with all authority. Let no one disregard you.
In reading these verses that encapsulate the gospel we are directly taught that we as disciples of Christ Jesus are expected to fullfil certain criteria or benchmarks:
we are to live sober, upright and godly in this life (so what happens when we lapse and no longer live like this?)
we are to endure and have patience waiting for the appearance of God our Saviour (what happens when disciples stop waiting?)
to redeem us from all iniquity and to purify for himself (what happens when disciples return to iniquity and are no longer pure?)
zealous of good works (that is often the easy part for even worldly people can do good works ).
Yes the prodigal son took his inheritance and squandered it in the world on wine, women and song and dwelt among swine (interesting Biblical reference there) But he came to his senses and repented and came back to his father;
who rejoiced that a sinner had come home. And they lived happily ever after.
But what of those who have departed from the faith and do not return? Do not repent? Remain in the world? That is not a mistake by God that He gave his grace to such people. Their sins are upon them. Their fickle hearts are their doing.
I know of my sister who never got the victory over cigarettes and so she over time quenched the Spirit. Now you would never know that she was once a Spirit-filled Christian. Her testimony and her walk have been corrupted.
Yes she still has the Holy Spirit in her for Jesus is ever faithful, but the Spirit is in hibernation waiting for her to come to her senses and repent. God will not force her to do so. She must love God and desire salvation.
The biggest danger for those who have fallen away and departed from the faith is time - they may either die or fail to repentant before our Lord returns.
Matthew 25:8 And the foolish said to the wise, ‘Give us some of your oil, for our lamps are going out.’
5:9 But the wise answered, saying, ‘Since there will not be enough for us and for you, go rather to the dealers and buy for yourselves.’
25:10 And while they were going to buy, the bridegroom came, and those who were ready went in with him to the marriage feast, and the door was shut.
25:11 Afterward the other virgins came also, saying, ‘Lord, lord, open to us.’
25:12 But he answered, ‘Truly, I say to you, I do not know you.’
25:13 Watch therefore, for you know neither the day nor the hour.