Romans 2:14-15

14 When Gentiles who have not the law do by nature what the law requires, they are a law to themselves, even though they do not have the law.
15 They show that what the law requires is written on their hearts, while their conscience also bears witness and their conflicting thoughts accuse or perhaps excuse them
Revised Standard Version of the Bible, copyright 1952 [2nd edition, 1971] by the Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.