In 1 Sam 26, David exemplifies a concept found throughout Scripture. And that is, the sacredness of the anointing and the authority of the LORD. David refused to do any harm to Saul a second time when he had come into his power, because Saul, even though he had turned wicked, had been anointed with anointing oil by Samuel, the LORD’s judge and prophet, to serve as king over Israel. Anointing oil is a shadow and type of the Holy Spirit in the Scriptures.
But David said to Abishai, “Do not destroy him; for who can stretch out his hand against the LORD’s anointed, and be guiltless?” David said furthermore, “As the LORD lives, the LORD shall strike him, or his day shall come to die, or he shall go out to battle and perish. The LORD forbid that I should stretch out my hand against the LORD’s anointed.” 1 Sam 26:9-11
David maintained this attitude, even though Saul was wicked, and was wickedly seeking to destroy David’s life — David, who had also been anointed by Samuel with oil to serve as the king of Israel. Because David honored the anointing of the LORD for the LORD’s sake, he refused to lift his hand or open his mouth against Saul for harm. He left it in the LORD’s hands: if the LORD wanted to remove Saul from his place, it would be the LORD who would do it, and not David.
Deu 16:18-18:22 is the part of Torah that expounds on and explains Honor your father and mother. This commandment teaches the principle that those human beings who have been anointed by the LORD to exercise authority in His name are to be honored as the LORD is to be honored. Since they themselves are under the authority of the LORD, the authority they exercise is His authority, and to respect and obey them is to respect and obey God.
(This is why is such a grave sin for parents to let their children get away with back talking, ignoring what they are asked, etc. — they are using the LORD’s office and anointing to teach them to dishonor godly authority, and that is a bad thing. Parents, it is not about whether your kids obey you – it is about whether they will grow up obeying God. And that is what you have to remember when you hear the lie that you are too tired or too busy or too distracted to take care of your children’s discipline.)
The first authorities and most important to honor, are of course, our parents. Parents are commanded throughout Scripture to walk in the ways of the LORD, but the LORD does not tell children to only honor those parents who are good or who do so. No qualifications are added to that command. And Deu 16:18-18:22 teaches us that parents are not the only ones who exercise the LORD’s authority and are to be honored as such. Other authorities who are to be honored, because they have been anointed by the LORD, are judges and officers (city officials); priests and Levites who serve the LORD in His tabernacle; kings; and prophets.
I should also add, that in the family, husbands also carry the authority of the LORD in their families. However, I believe the LORD framed the commandment to include father and mother on equal footing, to teach that husbands and wives within a family are in partnership. One is not to exalt himself over the other. See to it that the husband does not exalt himself over the wife in the family, and the wife does not exalt herself over the husband in the family. But the husband honors his wife because as the mother of his children, she carries the anointing of the LORD for authority over them. And the wife honors her husband because as the father of her children, he carries the anointing of the LORD for authority over them.
In matters of dispute, the wife yields to her husband in order to honor her head and honor the peace of her family (Gen 3:16). However, a wise man will not plow ahead with something to which his helpmate, who has been given to him by God, is opposed. But it is wisdom to wait patiently on the LORD until both husband and wife are in agreement.
So that is why David was loathe to dishonor the LORD’s anointed king, even though he was a wicked man. He left it up to the LORD to remove him if the LORD wanted him removed. And as we read with Abigail and Nabal, the LORD is perfectly capable of removing someone wicked, so that David could take his place, when it was the right time in the LORD’s timing to do so.