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.

No man can believe the gospel in and of himself; the power of the Spirit alone can lead anyone to belief; without it we are spiritually dead and lost and ruined and under the wrath of God.
Martyn Lloyd-Jones