They show that what the Law requires is written in their hearts, a fact to which their own consciences testify, and their thoughts will either accuse or excuse them

Don't you know that when you offer yourselves to someone as obedient slaves, you are slaves of the one you obey either of sin, which leads to death, or of obedience, which leads to righteousness?

For if God did not spare the natural branches, he certainly will not spare you, either.