Samuel, the last Judge of Israel, got to anoint the first two kings of Israel. The anointing of Saul, son of Kish, is told in 1 Samuel 9 & 10, while the anointing of David is in Chapter 16. Samuel had lead Israel since his youth and had been a prophet (seer) as well as the judge/leader of the nation. God revealed Himself to Samuel by visitation and His written Word and had used him in mighty ways.
Even with these credentials, the anointing of Saul and David was a faith act for Samuel. He got the “word of knowledge” about the tribe of Saul and his mission; he was even given the knowledge about the donkeys, but no name. Samuel had even made dinner plans (9:23), especially for Saul.
In 1 Samuel 10, the actual applying of the oil occurs with a very intriguing set of “signs” that had to be fulfilled. These were Saul’s faith builders; I will have more on them in another post.
There are some differences and similarities in the anointings that Samuel performed. Both Saul and David were anointed a second time in front of the nation. Saul’s first anointing was a very private affair; while David’s first one was done in front of his family and the other guest (possibly) at the sacrifice. Saul received the list of signs that were to be done and it seems that he took his office fairly soon. David, on the other hand, waited many years for the second anointing and him receiving his kingdom. It seems to me that Samuel spent quality time with Saul after the meal (9:25, 26) and again when they met in Gilgal (10: 8), but David only had the time when they were hiding from King Saul (19:18).