Doctrine & Covenants 88:84-85

Therefore, tarry ye, and labor diligently, that you may be perfected in your ministry to go forth among the Gentiles for the last time, as many as the mouth of the Lord shall name, to bind up the law and seal up the testimony, and to prepare the saints for the hour of judgment which is to come; that their souls may escape the wrath of God, the desolation of abomination which awaits the wicked, both in this world and in the world to come. Verily, I say unto you, let those who are not the first elders continue in the vineyard until the mouth of the Lord shall call them, for their time is not yet come; their garments are not clean from the blood of this generation.