Of necessity, authority in the religious realm must be determined either subjectively (internally, within man) or objectively (externally, outside of man). Jesus Himself views the above choices as the only possibilities to determine authority.
Consider Matthew 21:23-27: "Now when He came into the temple, the chief priests and the elders of the people confronted Him as He was teaching, and said, 'By what authority are You doing these things? And who gave You this authority?' But Jesus answered and said to them, 'I also will ask you one thing, which if you tell Me, I likewise will tell you by what authority I do these things: 'The baptism of John - where was it from? From heaven or from men?' And they reasoned among themselves, say-ing, 'If we say, 'From heaven,' He will say to us, 'Why then did you not believe him?' But if we say, `From men,' we fear the multitude, for all count John as a prophet.' So they answered Jesus and said, 'We do not know.' And He said to them, 'Neither will I tell you by what authority I do these things.'"
In this passage, Jesus asks the Jews if the baptism of John had its source with heaven or men. One of those alternatives had to be the correct answer. If there had been other alternatives available to them, do you not think those embarrassed Jews would have quickly forwarded one of them? They did not because they could not. Authority in religion is either from heaven of from men and the Bible makes it plain that proper authority in the spiritual realm lies with God not man.
Man has neither the ability nor right inherent within him to be his own source of authority. Jeremiah 10:23 states that it is not in man to direct his own steps. Proverbs 14:12 confirms, "There is a way that seems right to a man, But its end is the way of death."
Some suggest that one's conscience is a sufficient guide in religion. But the conscience, in and of itself and by itself, is neither an accurate guide nor proper authority in the spiritual realm. The apostle Paul, before his conversion, used his conscience as his guide and it caused him to do many "contrary (defiant) things" (Acts 26:9; 23:1). In the days of the judges of Israel evil abounded because "everyone did what was right in his own eyes" (Jud. 17:6).
Despite what Scripture says, though, mankind, over the ages, has sought to be its own authority and establish its own standards in the spiritual realm. These include such things as traditions (Matt. 15:13); opinions of family, ancestors (Matt. 10:37-39); and creeds of men (2 John 9-11). All of the standards in religion established by men, though varied, have one thing in common: they are all false. Since the wisdom of men is not from above, it is "earthly, sensual, demonic" (Jas. 3:15).