The life Christ gives is indeed eternal and everlasting.
The question between now and the end of your life is if you are going to continue to possess the life that is eternal.
And, actually, your possession of it is based on what you
believe.
What you do or don't do is just the result of what you believe.
We know what a person believes by what they say and what they do.
In the end, it's what you believe that determines if you will continue to possess the life that is eternal.
That's why we are exhorted to continue to believe and trust in Jesus:
"14 ...since we have a great high priest who has ascended into heaven...let us hold firmly to the faith we profess." - Hebrews 4:14
"23 Let us hold unswervingly to the hope we profess, for he who promised is faithful." - Hebrews 10:29