God commanded the prophet Isaiah to walk around naked for three years to symbolize Assyria's upcoming domination of Egypt and Ethiopia.
At that time the Lord spoke by Isaiah the son of Amoz, saying, 'Go and take the sackcloth off your loins, and take your shoe off your foot.' And he did so, walking naked and barefoot.
And the Lord said, 'Just as My servant Isaiah has walked naked and barefoot three years, for a sign and wonder upon Egypt and upon Ethiopia; So shall the king of Assyria lead away Egypt's prisoners, and the Ethiopian exiles . . . naked and barefoot, even with uncovered buttocks . . .' (Isaiah 20:2 - 4, HBFV throughout).
Isaiah's nudity symbolized, in a stark and open fashion, the upcoming utter overthrow of these two powers. It served as a warning to the Kingdom of Judah, who desired them as allies against Assyrian aggression (Isaiah 18 - 19, 30:1 - 7), that any trust placed on them (instead of God) would be in vain.
The minor prophet Micah was tasked with proclaiming prophecies against Samaria (symbolizing the Kingdom of Israel) and Jerusalem (representing the Kingdom of Judah) to the entire world (Micah 1:1 - 7). He was so grieved and devastated by what he foretold that he stripped off his clothes and publically bemoaned the punishment that was to come.
Therefore I will wail and howl; I will go stripped and naked; I will make a wailing like jackals ("dragons" in the King James Bible) . . . for her wounds are not curable; for it has come to Judah; it has reached to the gate of My people, even to Jerusalem (Micah 1:8 - 9).
Saul the nude prophet
King Saul grew to envy David's military successes and despised him as a rival for his throne. After an evil spirit came upon Saul, he attempted to assassinate David using a javelin (1Samuel 19:8 - 10). He then attempted to have him murdered while he left his house (verses 11 - 17).
Saul, furious that David fled to Samuel for safety, sends three sets of assassins to hunt him down. The killers, however, are diverted from their mission when God causes them to act like prophets when they see Samuel standing amongst his prophecy students (1Samuel 19:18 - 21)! Frustrated at his failure to take down David, Saul embarks on personally killing his rival. He is unaware that a naked surprise awaits him from God!
And he (Saul) went there to Naioth in Ramah. And the Spirit of God was upon him also, and going on he went and prophesied, until he came to Naioth in Ramah.
And he stripped off his clothes also, and prophesied before Samuel, even he. And he lay down disrobed all that day and all that night. Because of this they say, "Is Saul also among the prophets? (1Samuel 19:23 - 24).
God diverted Saul's attention by having him strip naked and act like a prophet so that David could escape and flee elsewhere (1Samuel 20:1)!
King David was a prophet as well as a king, as he revealed information concerning Jesus' life, trials and the suffering he would experience (Psalm 2, 22, 27, 31, etc.). As the Ark of the Covenant was transported to Jerusalem, he joyfully danced before it as an act of worship. Though not completely naked, he wore only a short linen garment during the procession (2Samuel 6:12 - 15).
Michal, David's wife, saw his energetic rejoicing and felt it necessary to sarcastically correct him for publically exposing his private parts.
And Michal the daughter of Saul came out to meet David and said, "How glorious was the king of Israel today, who uncovered himself today in the eyes of the handmaids of his servants, as one of the vain fellows shamelessly uncovers himself!" (2Samuel 6:20).
Michal was unable or unwilling to grasp the monumental significance of the Ark, representing the presence of God, finally coming into Israel's capital. Instead of being filled with joy and thankfulness before the Eternal she decided to make herself angry (2Samuel 6:16) by imputing evil to her husband's partially naked behavior.
David rightfully rebuked Michal for missing the entire point of why he danced and for failing to overlook the innocent exposure of his naked body. The king's appeal to God to justify his behavior seems to have led to Michal becoming childless the rest of her life (2Samuel 6:21 - 23).