It is important to emphasize that any thinkable service required can be provided by angles.
One of such services is tutelage.
Angels can teach you and make you understand things you cannot comprehend. They can do this through visions, dreams or can physically appear to do that. There are some examples in the Bible we can consider
Yea, whiles I was speaking in prayer, even the man Gabriel, whom I had seen in the vision at the beginning, being caused to fly swiftly, touched me about the time of the evening oblation. And he informed me, and talked with me, and said, O Daniel, Iam now come forth to give thee skill and understanding.Daniel 9:21-22 KJV
The whole book of revelation was revealed and taught John by an angel of the Lord.
The Revelation of Jesus Christ, which God gave unto him, to shew unto his servants things which must shortly come to pass; and he sent and signified it by his angel unto his servant John:
Revelation 1:1 KJV
If there is any subject you do not understand, it is time to activate the ministry of intellectual angels to come and give you skill and understanding.