Isaiah 30:21 says, " Your ears will hear a word behind you, "This is the way, walk in it," whenever you turn to the right or to the left." Does this prove that the Holy Spirit speaks to us audibly today?
This passage comes in the context of God warning Judah against trusting in other nations for salvation from Assyria. He is speaking to His rebellious children, the Jews, in this passage. Isaiah is told to write these instructions on a scroll/tablet that it would serve as a witness to the Jews (v8) because they are “a rebellious people, false sons, Sons who refuse to listen To the instruction of the LORD” (v9). They were rejecting the words that the prophets were telling them, instead desiring to have “pleasant words” spoken to them (v10). If they continue to trust in Egypt instead of repenting and turning to God, God will allow them to be crushed and taken into captivity (v12-17).
But in spite of their rebellion, God will still be gracious to them. He longs to be gracious to them (v18). When they cry to Him because of their oppression that He brought upon them, He will answer them (vs18-19). He will continue to be their teacher and bring them back when they turn off the straight way He has given them to the right and the left (v20-21). God’s words will turn them back to Him, lead them to destroy the graven images that they, the Jews, have made to worship (v22). Then the Lord would bless their land (Jerusalem and Judah) with rain so they can have crops and food and running streams (no more famines as punishment for their sins and alliances with Egypt: vs23-25). The Lord will bring light to their times of darkness and heal the bruises He has given them because of their sin against Him (v26).
Then the Lord will come with words of judgment upon His enemies, specifically Assyria. He will be a consuming fire to Assyria, and bring fear upon them because his people were again turning to Him and worshiping Him (vs27-33).
With the previous description of the context, I believe we can clearly see who the Lord is talking to in verse 21. He is talking to the Jews in Judea who were trusting in Egypt to deliver them from Assyria who had come against the land and had already taken Israel into captivity. Before and after the passage in question, the Lord speaks of their specific historical context. They were trusting in Egypt (before) and He would judge the Assyrians (after).
In verse 21, He is telling his people that if they turn off of the path of righteousness, He will call to them to bring them back to Him. Up to this point He has been doing this through the Prophets, and He will continue to do so because He cares for His people. He will always be reaching His hands out to His disobedient people and calling them back to Him through the prophets until there is no response to Him:
“The LORD, the God of their fathers, sent word to them again and again by His messengers, because He had compassion on His people and on His dwelling place; 16 but they continually mocked the messengers of God, despised His words and scoffed at His prophets, until the wrath of the LORD arose against His people, until there was no remedy” (2 Chronicles 36:15-16).
This is how scripture tells us God continued to call out to His people who have turned their backs to Him. There is no evidence that the passage is talking about a special audible voice that the Holy Spirit/ God uses to call His people to Him outside of His prophets (who later had their words recorded in scripture).
There are applications today from this passage, of course. It encourages us not to trust in things other than the Lord to be the one who delivers us. It teaches us that the Lord cares for us, even when we turn our backs on Him and leave the path of righteousness. He also, as our Shepherd, calls out to us through His servants who preach and teach His word to call us back to Him when we fall.
This particular passage is not promising an audible voice of God to us. He in those times used His inspired messengers who had their writings written down as scripture to call His people back to Him. If this is what He is referring to in this passage, why would we apply it to us differently in saying that God gives as a still small voice to nudge us in a certain direction in reference to a job choice, a person to marry, or other decision we need to make. The passage in question is not referring to these kind of situations, but only God calling His rebellious people back to Him.
In scripture, we only see God speak to Christians audibly who were inspired to the Spirit to be Apostles or prophets. This is what we also see in the Old Testament with God’s prophets. I do not know of a passage of scripture, especially in the New Testament which teaches that God or the Spirit leads us audibly or gives us messages/nudges outside of the teaching of the scriptures. This is usually just assumed into passages which talk about how the Spirit leads.