“For the grace of God has appeared, bringing salvation for all people, training us to renounce ungodliness and worldly passions, and to live self-controlled, upright, and godly lives in the present age,waiting for our blessed hope, the appearing of the glory of our great God and Savior Jesus Christ, who gave himself for us to redeem us from all lawlessness and to purify for himself a people for his own possession who are zealous for good works.”
J. C. Ryle talks about what it means to be zealous:
Zeal in religion is a burning desire to please God, to do His will, and to advance His glory in the world in every possible way… A zealous man in religion is pre-eminently a man of one thing. It is not enough that he is earnest, hearty, uncompromising, through-going, whole-hearted, fervent in spirit. He only sees one thing, he cares for one thing, he lives for one thing, he is swallowed up in one thing; and that one thing is to please God. Whether he lives, or whether he dies—whether he has health, or whether he has sickness—whether he is rich, or whether is poor—whether he pleases man, or whether he gives offence—whether he is thought wise, or whether he is thought foolish—whether he gets blame, or whether he gets praise—whether he gets honor, or whether he gets shame—for all this the zealous man cares nothing at all. He burns for one thing; and that one thing is to please God, and to advance God’s glory. If he is consumed in the very burning, he cares not for it—he is content. He feels that, like a lamp, he is made to burn; and if consumed in burning, he has but done the work for which God appointed to him (Quoted in Packer, Knowing God, 173).
Why would we be zealous in this way? Because, the text says, we are “waiting for our blessed hope, the appearing of the glory of our great God and Savior Jesus Christ.” Jesus is coming back! We want to work for Him. We want to be found faithful on the day when all shall give an account. We are zealous because we know what is meant by “the appearing of the glory of our great God and Savior Jesus Christ.”