Have we lost the context around what Paul is saying in Romans 10:9.

The phrase 'declare with your mouth, "Jesus is Lord"' was the equivalent of invoking a death sentence. Caesar was no longer king, no longer god.

You'd be offering to give up everything you knew and were comfortable with to follow Jesus.

There are many places and cultures in this world that is still true.

Romans 9:1 and Romans 10:9