other · 318 · Alexandria
Its argument runs in one line: humanity was made in the Image and had defaced it, and only the Image itself could restore what was made after it. From there he takes the objections in order — that death by crucifixion is shameful, that a body is beneath God, that the thing has changed nothing — and answers the last of them empirically, by pointing at people who no longer fear dying. What is striking about it in this dataset's terms is the date. It is written before the Arian controversy broke, by a young deacon of Alexandria who would spend the next fifty years and five exiles defending a single word he had not yet needed. The book is not about Arius. Everything he did afterwards is downstream of it.
To answer why God would become a man at all, and why that particular death.
The book C. S. Lewis told modern readers to open before any other ancient one, written by a deacon before he had a controversy to win.