As the Lord’s agents, as his servants, as ambassadors of Christ—sent by him, sent to speak in his place instead, sent to say what he would say if he personally were here—we testify that no man, as long as the earth shall stand, or the heavens endure, or God continues as God, no man shall ever be saved in the kingdom of God, in the celestial kingdom of heaven, without doing the works of righteousness.
Elder Bruce R. McConkie, "What Think Ye of Salvation by Grace?", BYU Speeches, January 10, 1984
There is a very popular notion throughout all of Christendom that says we are saved if we just believe in Christ. We can go on committing sin. We can continue doing whatever we want. We can "eat, drink, and be merry". It doesn't matter, as long as we profess with our lips the Savior to be King. To be our Lord.
Seems to me that this was Lucifer's plan in the grand council of heaven. He wanted to save everyone despite agency, despite works, and despite character. Here, on earth, he has modified this plan a bit, telling us that is okay to believe in Christ, but still do what you want.
We, as believers and followers of the Lord's truth, the Lord's Plan, we know better. We know that it is not possible to be saved, to have eternal life, without developing our character to equal that of Christ's. Granted, it was Christ, Himself, that even made it possible to be saved in the first place. Now, we have to do the work to enjoy that gift.