Q. Does everyone have God’s moral laws innately stamped on their hearts regardless of whether they know Scripture or have access to it? Paul wrote to the Romans that “since the creation of the world, God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made.” But he also wrote that “when Gentiles, who do not have the law, do by nature things required by the law, they . . . show that the requirements of the law are written on their hearts.” Does that mean we are not only cognizant of the existence of God, but also without excuse concerning obeying His laws?
God did say through Jeremiah, in a passage later quoted in the letter to the Hebrews, “I will put my laws in their minds and write them on their hearts.” But this promise was made specifically to those who would become part of the new covenant by trusting in Jesus. And in context, it refers to people not just knowing God’s laws, but obeying them willingly and eagerly, because they are being transformed within by the Holy Spirit.
The comment you quote from Paul’s letter to the Romans about the Gentiles keeping the law is actually talking about something different. It says literally in Greek that the work of the law is written on their hearts—not the specific requirements of the law, but what it looks like to “do” (live by) the law. Paul talks immediately afterwards about the conscience bearing witness along with the heart, i.e. at the same time—not “also” or “in addition,” as many translations have it. I therefore think these two versions capture his meaning pretty well:
“The conscience is like a law written in the human heart.” (CEV)
“In their hearts they know what is right and wrong, the same as the law commands, and their consciences agree.” (ERV)
Similarly, when Paul writes just before this that at times Gentiles “do by nature what the law requires,” he’s using a phrase that’s synonymous with “conscience.”
The whole point of Paul’s argument here is to respond to the claim of the church in Rome, to which he’s writing, that the Jews have a greater right to the gospel. (“To the Jew first” seems to have been their motto.) Paul is working to transform this claim into a recognition that Jews and Gentiles have an equal need for the gospel. (“To the Jew first, but also to the Gentile.”)
And so, he argues, the Jews have the law, but they haven’t kept it; the Gentiles have conscience, but they haven’t followed that, either. (Most of the time, that is; they are capable of following it). Both groups have failed to follow the means of moral guidance that God has given them, and as a result, “All have sinned and fall short of the glory of God,” but all can and must be “justified by his grace as a gift, through the redemption that is in Christ Jesus.”
So in this statement about the Gentiles, Paul is basically saying that everybody has a conscience that enables them generally to know right from wrong in their hearts. If they don’t follow their conscience, they can’t plead that they didn’t know any better. They need to admit that they’ve done wrong and come to God for forgiveness and justification by grace.
In short, while everybody may not have God’s actual moral laws innately stamped on their hearts, the Bible does say here that everybody has a conscience. However, we should recognize that a given person’s conscience, and thus their sense of right and wrong, will be influenced by their own family, society, and culture. Nobody starts out with a “blank slate,” the conscience they would have simply by understanding about God through the creation.
In addition, unfortunately, it’s possible to disregard or resist our conscience to the point where it becomes hardened and is no longer a reliable source of moral guidance. As Paul puts it in a vivid phrase in his first letter to Timothy, the conscience then becomes “seared as with a hot iron.” This frightening possibility should make us all eager to maintain a tender conscience before God!