I found a great passage in Sam Storms book Signs of the Spirit that points to a great theme of Christianity: perseverance.
"There is hardly anything more explicit in the teachings of Jesus himself than the rules by which we are to judge the sincerity of someone's profession o faith. we must judge the nature of the tree by the quality of its fruit. But if the fruit of saving virtue is subject to being counterfeited, what good is this as a rule for discerning true from false? The answer is found not in the mere presence of what appears to be fruit, but in its perseverance. If the fruit shows itself not merely once, no matter how fervently and sweetly, but endures and matures over time and through trial, we can more solidly judge whether they are be truly of God (although even then our judgement is still fallible).I quote Same Storms not because I'm particular interested in judging (or meditating) on whether others are sincere in their faith, but whether I am.
Paul writing in his 1st letter to the Corinthians:
24 Do you not know that in a race all the runners run, but only one receives the prize? So run that you may obtain it. 25 Every athlete exercises self-control in all things. They do it to receive a perishable wreath, but we an imperishable. 26 So I do not run aimlessly; I do not box as one beating the air. 27 But I discipline my body and keep it under control,  lest after preaching to others I myself should be disqualified (ch. 9).Father, give me the strength to run the race with perseverance. Give me endurance, Father. In Jesus name, Amen.