Once we are saved, we are always His. Bible says there is no condemnation to those who are in christ Jesus.
But my point on discipline and the Lord working in us here is some scripture
But if you are without discipline — which all receive[fn] — then you are illegitimate children and not sons.
Furthermore, we had human fathers discipline us, and we respected them. Shouldn’t we submit even more to the Father of spirits and live?
For they disciplined us for a short time based on what seemed good to them, but he does it for our benefit, so that we can share his holiness.
No discipline seems enjoyable at the time, but painful. Later on, however, it yields the peaceful fruit of righteousness to those who have been trained by it.
Hebrews 12:8-11