We have the responsibility to communicate the gospel as clearly as possible.

We confess that our salvation is in God's hands from first to last. We know that we cannot contribute to our salvation in the least. Nor can we make the gospel more effective by our efforts.

Won't those truths make us spiritually lazy?

One sainted Wisconsin Lutheran Seminary professor put it this way:

But, someone might say, will not the fact that God, and God alone, grants faith and that he does so just when and where he pleases tend to make us careless? If there is nothing we can contribute toward our own faith or toward that of others, why then make any effort?

The very opposite. It will drive us to work out our salvation with fear and trembling. So St. Paul says. He encourages the Philippians to work out their salvation with fear and trembling (Philippians 2:12) and then added this reason: "For it is God who works in you to will and to act according to his good purpose" (v. 13).

This reason may seem odd: you work out your salvation because God is doing it for you from A to Z. Yet this is the very nature of the faith which the Holy Spirit works in our hearts that on the one hand rejoices in the great gift of God, and at the same time begins to work as if the whole matter rested in our own hands (John Meyer, Studies in the Augsburg Confession, p. 82).