Martyn Lloyd-Jones
When a man says, 'Because I have sinned I have lost (salvation)', what he is really saying on the other side is, 'I had it because I was good.' He is wrong in both respects.

I planted, Apollos watered, but God gave the growth. So neither he who plants nor he who waters is anything, but only God who gives the growth. He who plants and he who waters are one, and each will receive his wages according to his labor.
1 Corinthians 3:6-8