Several Bible verses tell us that special people such as kings and priests were anointed as a sign of their appointment:
30 Moses took some of the anointing oil, and some of the blood which was on the altar, and sprinkled it on Aaron, on his garments, and on his sons, and on his sons’ garments with him, and sanctified Aaron, his garments, and his sons, and his sons’ garments with him.
1 Samuel said to Saul, “The LORD sent me to anoint you to be king over his people, over Israel. Now therefore listen to the voice of the LORD’s words.
7 Nathan said to David, “You are the man. This is what the LORD, the God of Israel, says: ‘I anointed you king over Israel, and I delivered you out of the hand of Saul.
34 Let Zadok the priest and Nathan the prophet anoint him there king over Israel. Blow the trumpet, and say, ‘Long live king Solomon!’
Jesus told his disciples that they would be given help in their teaching and remembering what Jesus had said:
26 But the Counsellor, the Holy Spirit, whom the Father will send in my name, will teach you all things, and will remind you of all that I said to you.
The apostle John tells believers in the first century that their anointing has enabled them to know what is true teaching:
20 You have an anointing from the Holy One, and you all have knowledge.
27 As for you, the anointing which you received from him remains in you, and you don’t need for anyone to teach you. But as his anointing teaches you concerning all things, and is true, and is no lie, and even as it taught you, you will remain in him.