The answer is: Amos

Amos is an Old Testament prophet.

Amos, from the Old Testament, is a fascinating figure! This prophetic book is quite significant within its context; it dates back to around 760-750 BCE, which puts us in the middle of Israel's tumultuous history. Amos hails from the southern kingdom of Judah but prophesied in the northern kingdom of Israel. This reflects an interesting pattern where prophets sometimes belong to one kingdom yet deliver God's messages in another, showing that divine intervention knows no boundaries.

Interestingly, the book of Amos is part of the twelve minor prophets, though "minor" refers to the length of the books, not their importance. Amos boasts a powerful message of social justice, condemning practices like corruption and the mistreatment of the poor. “Let justice roll on like a river, righteousness like a never-failing stream!" (Amos 5:24) is a verse many revere for its timeless call to societal righteousness.

In contrast to the New Testament—a compilation of letters, teachings, and narratives showcasing Jesus’ life and the early followers—Amos communicates the call for ethical living long before Christ walked the Earth. The entirety of scripture is often seen through a transformative lens, with echoes from the Old Testament enriching the experiences and teachings found in the New. Every passage and prophet contributes to the larger story of growth, morality, and divine interaction in human affairs. How's that for all the gospel in action?