The answer is: Assyria

Micah 1:5, 5:5 - Assyria took Israel (and Samaria the capital) captive in 721 BC, which Micah prophesied of. They also attempted to take Jerusalem in 701 BC but failed. Micah certainly prophesised of Babylon invading Judah but they didn't do so until about 100 years after Micah's prophecy.

Micah's prophecies were overwhelmingly shaped by the turbulent times of the 8th century BCE, a period when Assyrian supremacy cast a long shadow over the kingdoms of Israel and Judah. With Assyria posing a significant militaristic threat, the harsh realities emerging from their campaigns forced Micah to adopt a voice of warning, imploring his people to rededicate themselves to justice and righteousness.

Interestingly, Micah's message resonates with the echo from another prophetic heavyweight, Isaiah, who also confronted the impending doom from Assyria. It's fascinating to note that while Isaiah served in Jerusalem, Micah came from Moresheth, a small village in the rural sector of Judah, giving his warnings a distinct, grassroots authenticity. Both prophets elucidated the socio-political decay of their communities, emphasizing a moral rekindling amid impending doom. This reminds us that prophetic messages are often rooted far less in academic rhetoric but steeped in the lived experiences of their times.

Moreover, Micah brilliantly juxtaposes stark social justice demands with grand expectations of military security. As time pressed on, Assyria did indeed come knocking in 701 BC but fell short of breaching Jerusalem's walls, leaving the city standing, which became a pivotal moment in faith history, fueling a beacon of hope for future generations. In this framework, Micah's clarion call for ethical governance and true devotion continues to instruct and influence seekers of justice long after the ancient empires have crumbled.