Justification by grace empowers and spreads sanctification by grace.
I think of my inner self as a globe, a world, with many dark continents still unexplored, uncivilized, vast jungles of primitive impulses. But Jesus the Liberator steps ashore on the coast of one of those continents, plants the flag of his kingdom in my consciousness and declares peace. That is justification.
Then sanctification begins. For example, it doesn’t take long for a half-naked savage to run out onto the beach with spear in hand to attack Jesus. This is some selfish desire in me rising up against the King. But he declares peace all over again and subdues that aspect of me by the force of his grace.
The King starts moving steadily inland, planting his flag in ever new regions of my being. He brings one dark thing after another into my awareness, declares peace again and again and again, and thereby establishes civilization.
Sanctification works as I re-experience the surprise of justification, applied to new points of need.