These tactics (1 Samuel 21)

“The king has sent me on a private matter,” David said.  “He told me not to tell anyone why I am here.”

David was on the run from Saul, who was out to kill him.  Here he lies to Ahimelech the priest in order to conceal that fact, and possibly in an effort to protect Ahimelech and his family.  Later, he acts like a man insane before the king of Achish, so as not to be discovered.

The scripture is silent concerning God’s opinion of these tactics.  Ultimately, truth is not relative, yet God works in and through the choices that we humans make.