1 Samuel 24:8

David also arose afterward
After Saul was gone: and went out of the cave;
where he had been all the time that Saul had been in it: and cried after Saul:
with a loud voice: my lord the king; by which titles Saul would know that he was called unto: and when Saul looked behind him;
to see who it was that called unto him: David stooped with his face to the earth, and bowed himself:
giving reverence and honour to him as a king; (See Gill on 1 Samuel 20:41).