On Oracles & Visions

I'm admittedly not entirely clear on the concepts of oracles and visions. In Amos, Bullock asserts oracles and visions comprise the two literary centers in Amos.  

The Hebrew words for oracle may be translated as “burden,” “saying,” “word,” etc. The words can be translated in different ways, even within the same book/author.  The word oracle can be ascribed to an entire prophetic books or to a part of one.  

In one piece of Amos, the King James renders it, "Thus saith the Lord" Encyclopedia.com elaborates on this usage, "The technical term for an oracle of a prophet is n e'  It occurs 361 times in the Hebrew OT, mostly in the books of the "writing" Prophets, where it generally stands at the end of a short oracle given in Yahweh's name, traditionally rendered in English as "Thus says the Lord." It serves as a sort of signature guaranteeing the authenticity of the oracle." 

Because they were God's word, these pronouncements were true, even though they could be changed as in the case of Jonah's pronouncement over Nineveh (Jonah 3:4-9 ). Music can be involved, "But now bring me a minstrel. And it came to pass, when the minstrel played, that the hand of the LORD came upon him." 2 Kings 3:15

 This entry on oracles from the Holman Bible Dictionary via Study Light is excellent because it teases out the complexities a bit more. Beginning with an all purpose definition, "communications from God," it moves into the nuances of how this concept is worded and translated, differences between how it is used in the Old Testament or New, how it is used by pagan nations or by Israel, subcategories and ways oracles can be received and expressed.

Notes from this dictionary:

Transmission of Oracles

There are diverse ways that oracles and visions could be received and perceived--literally received through their senses or received in their minds. 

"Frequently, the Old Testament gives no indication as to how God communicated His pronouncement oracles to His prophet or priest. Careful reading of the Old Testament shows a variety of methods in use. The frequent use of sights in pronouncements has led some to believe that the prophets had encounters with God that later they had to interpret and communicate to others. Regardless of how the oracle came, it was to be expressed to others. This expression seems most often to have been oral." -HBD

"Two points should be recognized. First, oracles were remembered long after their pronouncement. When Jehu killed Joram (2 Kings 9:25 ), he had the body taken to Naboth's vineyard in order that an oracle pronounced in Ahab's day might be fulfilled. Second, though we do not know the response of the original hearers, God's pronouncements are still being read and are producing change in people in our day. Thus, the oracles are still functioning. See Inspiration; Priest; Prophet; Spirit." -HBD

Exigence and Purpose of Oracles

Sometimes an oracle is a response to a question and other times, it's a straight declaration without the framework of a question.

There are decision oracles vs. pronouncement oracles. Sometimes decision oracles involved use of an object, "lots," urim and thumen, but other times not. Decision oracles were God's response to questions and concerns in the present. They did not condemn sin or predict the future in any specific sense.

Pronouncement oracles are often interpreted as divine words of punishment or judgment. However, it is possible for an oracle to bless, as was the case with Baalam. The word oracles in the New Testament most often refers to the teachings of God in the Old Testament (Acts 7:38; Romans 3:2 ). It may refer to Christian teachings, too (Hebrews 5:12 ). -HBDictionary

"One caution about prophets and their pronouncements must be made. Often the prophets were not prophets until they received God's word (consider Amos' experience in Amos 7:14-15 ). The word came to some reluctantly as in the case of Jeremiah. God's giving of an oracle to a man or woman made them a prophet; for, when the divine word came, the prophet had to speak (Amos 3:8 )."