The way is narrow, we may walk on it for a while and fall away. Man never was 'eternally saved', so there is no way we can question whether he was 'saved' or not. He had been saved, just as those who are in Christ were, only he didn't persevere. Christ never speaks of the assurance of glory, only the hope of it. We have a Lord to attain and be conformed to!
The Lord says 'abide in me and I in you'. We are to be in Christ, and ABIDE there, yes, that is up to us.
God loves all, he did not pick us to be his children because he 'loves us more'. We were chosen that we might shine his light and do his works. If a man only knows the law, he is held accountable by the Lord to be obedient in that. If a man has a revelation of Christ Jesus, he is held accountable to be obedient to the revelation. Otherwise God loves those who received more, more. But God is not a respecter of persons.
If we have been called by the Lord we should fear Him, knowing we have received favor and must answer as to what we did with it. Burrying a talent and saying 'there, I have the talent, I'm saved' is a dangerous path to tread. We are to bear fruit with what God gives, otherwise we are unfaithful servants, and will be cut off and cast out.
The grace of God is a tool, an empowering so that we can be like him and do what pleases him.