1 Samuel 24

1 Samuel 24:4

And again when the men who were with him counselled David to slay Saul, through his simple mind he refrained. That they should counsel him to slay his enemy arose from the cunning and craft of this world, for it is the custom of those who are filled with the cunning of this world to act craftily to remove obstacles from their path; but David in his simplicity and mercy refrained. — 13 Ascetic Discourses, Discourse 4 -- On Faith: First Discourse on Simplicity