If you persevere to the end, then you were saved.
That is then - future - but what about now?
Yes that is in several places in the NT especially Revelation chapters 1-3. The blog that started this thread concerns me, because it seems this is not a hypothetical question but something witnessed. MacArthur gave an interview on his book "The Gospel according to Jesus Christ" where he gave some personal encounters of people who professed to be Christian and then later became atheists or boastful repeating sinners. Some went to college and seminary with him.
But I digress. If we fail to know that God is Sovereign in Salvation, then these matters will continuously bug some. There is always the point of properly defining words. Repent means to turn away from our sins. Faithfulness is congruent to faith. What I would be interested in finding out is if the example of the youth pastor has an ending story. Does he ever come back? IMO if he is saved, he will come back and confess and repent and rejoin fellowship. If he doesn't IMO, he never knew Christ.
ALL things are by grace. As is our perseverance.
Romans 8: 32 He who did not spare his own Son, but gave him up for us all--how will he not also, along with him, graciously give us all things? 33 Who will bring any charge against those whom God has chosen? It is God who justifies. 34 Who is he that condemns? Christ Jesus, who died--more than that, who was raised to life--is at the right hand of God and is also interceding for us. 35 Who shall separate us from the love of Christ? Shall trouble or hardship or persecution or famine or nakedness or danger or sword? 36 As it is written: "For your sake we face death all day long; we are considered as sheep to be slaughtered." 37 No, in all these things we are more than conquerors through him who loved us. 38 For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, 39 neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord.
Correct. And God helps us with the strength to carry on