And because iniquity shall abound, the love of many shall wax cold. But he that shall endure unto the end, the same shall be saved. Matthew 24:12-13
Endurance - noun - To continue, despite fatigue, stress, or other adverse conditions.
Work out your salvation with fear and trembling. Philippians 2:12
But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway. I Corinthians 9:27
And Jesus said unto him, No man, having put his hand to the plough, and looking back, is fit for the kingdom of God. Luke 9:62