How do we know Jesus is our all in all?

In the sermon, it is stated that Christ's fullness is meant for our emptiness and His righteousness is meant for our sin. As long as we recognize ourselves as poor sinners, we can certainly affirm that Jesus is our all in all. The essence of salvation lies in this relationship; the awareness of our need leads us to fully depend on Christ, who fulfills every requirement for our redemption. Thus, in acknowledging our insufficiency and Christ's sufficiency, we can be assured of His lordship in our lives.