No, I don't think it's a waste of time. I was, rather, stating where the logic leads, if you insist on a theology which states that "works" have no effect on salvation. Because preaching the Gospel is "a work."
Bible-believing Christians, however, know ....
Are you suggesting, then, that I don't believe the Bible?
As Christ told us in the excerpt from Luke, preaching the Gospel is our "duty."
Good works are the evidence of our salvation; not a requirement for it. A works-based salvation is denounced throughout Scripture.
But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness." -- Romans 4:4-5"Now to him that worketh is the reward not reckoned of grace, but of debt.
Or read the entire book of Ephesians. Or Hebrews.
Protestants make a distinction between justification and sanctification and both are under the umbrella of salvation. Justification before God involves no amount of works and is strictly by the instrument of faith based on the perfect righteousness of Christ.
It is also important to note that the works component in sanctification comes with a decidely different motivation than the Greeks or Romans. For the Greeks and Romans the works component is motivated by a desire to acquire merits for final salvation. Those who believe in the doctrines of Grace approach works from a different motivation. Having an assurance that they have been reconciled to God through a work of someone else outside of themself, Christ, the motivation for works is one of extreme gratitude.
I believe the Scripture record is clear that our justification is none of our own doing and works reflect a truly reconciled sinner.