Our rest is written about in Revelation 14:13, where John says,

And I heard a voice from heaven, saying, “Write, ‘Blessed are the dead who die in the Lord from now on!'” “Yes,” says the Spirit, “so that they may rest from their labors, for their deeds follow with them.”

From this verse we may affirm that the souls of all those who die in the Lord (and also, all those who are raptured) will be at rest from all labor and strife of being in an ungodly world and of the sins of the world. But, in contrast (from verse 11), all those who are not believers will have no rest day and night for eternity. Here, in the context, it speaks of those unbelievers during the Tribulation who receive the mark of the beast; but it will be the same for all unbelievers—they all will have no rest, only torment and strife. Therefore, this rest we speak of here (in verse 13) is a serenity of the soul, a peacefulness of a life made perfect in holiness by the blood of our Savior. And it is even that way now when we confess our sins and resolve to obey Him. He lets us rest in Him and we are at peace; thus, for all of eternity in heaven we will have that same rest—and an even greater rest.