I love to hear that phrase but at the same time I understand as I get older that there are several kinds of attitudes that can make living that phrase a reality.
Pride has a kind of faithfulness and steely strength that won't bend, move or stop because it will lose something or being lessened in someone else's eyes. Pride just won't be the first one to quit because it thinks it is better.
But, There is another kind of 'don't quit' this one is gentle and draws no attention to itself at all.
"For at one time you were darkness, but now you are light in the Lord. Walk as children of light (for the fruit of light is found in all that is good and right and true), and try to discern what is pleasing to the Lord." - Ephesians 5:8-10 ESV
"But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law. And those who belong to Christ Jesus have crucified the flesh with its passions and desires. If we live by the Spirit, let us also keep in step with the Spirit." - Galatians 5:22-25 ESV
I want my 'yes' to be 'yes' and my 'no' to be a big fat 'no'. I for one want to quit everything that is dark and keep in step with what is in the light. Pride won't let me quit but I must. God has given me something wondrous to say 'yes' to.
Faithfulness is the 'don't quit' I desire to live in. But, I've seen the faithfulness born or pride and not born as a fruit of the Holy Spirit. It is arrogant. If I point the finger anywhere it isn't going to be outward. I am the man. I am the bull who sometimes goes but knocks people over going. I am the one who won't quit because he doesn't want to be a quitter.
Oh, But then I see Jesus.
He is just over there. He is just behind the closed door. He Is worshiping in the chapel. He is standing in the place where we don't have a church yet. He is in each room looking at people and loving them. He Is with me but He Is also just over there... a few steps past me... love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control are just over there waiting to born into the world.
I can't quit. I want to be there with Him. My wife needs a husband. My mother needs a son. My sister needs a brother. People need a preacher. That place needs a Church. A dead building on each corner won't cut it. They need a living Church. People need to see Him and then some will also drop their nets and follow Him once they see the power that is there in Him.
Jesus the eternal One never quits because He would have to affected by time and space and to do that. He would have to change or be discouraged and He never does either of those things. He Is ever and always faithful. Basking in His light we never need to stop. There is new life in every step.