I've read a few commentators who say something like "anointing is a
prototypically 'royal' or 'kingly' action." And it certainly is there, starting in 1 Samuel (2.35, 10.1, etc.).
But before that point, anointing is a uniquely
tabernaclely action. In Ex 40, for example, God commands Moses, saying, "take the anointing oil and anoint the tabernacle a
nd all that is in it" (v. 9), specifying all the utensils, the altar, the
laver, and Aaron and his sons.
Now, perhaps, this constitutes Aaron and his sons as a "royal" priesthood. But I don't know. Israel herself is supposed to be the royal priesthood (Ex 19.6, cf., 1 Peter 2.9). There's no indication that this designation is removed from Israel and given only to Aaron and his sons.
Instead, I wonder if the action moves the other way. Prior to the creation of the monarchy in 1 Samuel, Israel is ruled by judges (and led into battle by Spirit-inspired "major" judges). Kingly powers are redundant with many of the
judgely powers.
There are several distinctions, however, between judges and kings. One of these is that kings are anointed while judges were not.
Rather than thinking that anointing then is some sort of distinctively "kingly" event, I'm thinking that perhaps anointing is a
tabernaclely thing that integrates the king directly into Israel's cult, something that did not happen to the
unanointed judges. And so the development of the monarchy in Israel is primarily a
cultic development rather than a political or military development.
I'm of course not suggesting that judges did not have a role to play in Israel's cult, only that the king is more directly tied to the cult than the judges were -- kings are anointed like the other utensils in the tabernacle, and so "belongs there," as it were, in a way that the judges did not. (Given the
Edenic motif of the tabernacle, perhaps this is emblematic of restoring Adam's otherwise lost royal prerogatives.)
This, in turn, might account for the continuing concern of Israel's king with the temple, and aspiration not shared by the judges.
But I don't know. It just seems that the idea of "anointing qua tabernacle action" is a really fertile source of thinking about the role of the king in Israel (and in God's plan more generally). Writing off anointing as a kingly action, while not incorrect, seems maybe to emphasize the wrong thing, and so misdirects our eyes away from the way that anointing seems to integrate the king into the cult in a way that judges were not. And that that's the big change in the movement from judges to kings.