There's a lot more to it than that. Repentance is never "secured" for all time. We need to learn humility...a new humility to add to the new growth. This is real life and anything is possible. We are just human after all.
You always want to add to what Jesus did, and that's a huge mistake.
We are just human, and coming to understand what we actually are is humilty. Humility is not something you learn, it's something you realize. If you understand the importance of the distinction.
And yet we are no longer "just human". We who are born again, if you are born again, we are now recreated sharing God's Own nature, and that's anything But "Just human".
Therefore, once repentance is secure, all one need do in order to keep bearing the right kind of fruit is to keep walking in the same direction; and not turn back around towards sin.
Repentance - metanoia - is the exchange of the mind of the flesh for the mind of Christ, and with that new mind we learn to live a new life, Christ's life through us.
I say learn, not that we learn to live that life, His life comes through us, as we learn to allow Him to do this, by learning to trust in His redemption of us, purchasing us to Himself.
As we come to understand that we are the children of God . . . created, then recreated to be in love with Him, as He loves us, we will give ourselves more and more into that most abundant and joy filled life.
They who claim salvation at the beginning are in great danger of not bearing the right kind of fruit...of "burying their talent"...or their potential to be like Christ in the world.
Give your warnings, they are suitable for the unsaved. Each needs to make their calling and election certain.
We have passed from death into life. We are translated from the kingdom of darkness . . . into the kingdom of the Beloved. We are new creations. We are in Christ. Justified in Him. Righteous in Him. Holy in Him. Not theories, not metaphors. Facts.
Much love!