21 But if you do warn the righteous man not to sin and he does not sin, he will surely live because he took warning, and you will have saved yourself." (Ezekiel 3)
We have to, we need to, we should all spread the truth of the gospel. It is so hard to approach people with this topic because we're afraid of rejection and overreactions, but God told Ezekiel not to be afraid, and neither should we fear. There are two possible results, both of which are likely. The first is that they do reject us and put us down. It's plausible. It's reasonable. It's very, very likely. However, the second is that they repent.
Either way, our responsibility is to share the good news. It is never promised that we will be received well. It is not expected that everyone we meet should turn from their ways. Regardless of the outcome, we will be successful in our mission because we have been faithful to the comission. We just have to be sensitive to God's plan, and seek wisdom when speaking to non-believers.