Justification is process by which we are made right with God, via his holy Spirit within us enabling us to resist and overcome sin, to become more and more renewed in the image of the Creator–made holier and holier, in other words. Justification and sanctification, while distinct concepts, are undeniably intertwined:
Martin Luther said: “There is no justification without sanctification …”
Sanctification is a part of justification, and vice-versa. As we’re made “right” with God, we’re made “holy,” as well. How can we be right with him, in the first place, without being “holy”? Cooperating with his Grace, we allow our holiness to grow; in allowing our holiness to grow, we become increasingly pleasing in the eyes of Our Maker. Ultimately, it is he who initiates and finishes this, however. We simply choose whether or not to allow him to do so, and at any given point in time we can stop this process.
Both begin at baptism and continue throughout the faithful Christian’s walk. We will not leave this world totally sanctified, though, and this is a process which ultimately sees its end in the next Life–through the fires of purgation. We are then brought before the Throne, into the glorious Presence of Our God in Heaven, now worthy through his own infinite merits and love, to stand before him.