A fork in the road is a metaphor, , for a deciding moment in life or history when a choice between presented options is required, and, once made, the choice cannot be reversed.
<blockquote>"Mortal, mark out two roads for the sword of the king of Babylon to come; both of them shall issue from the same land. And make a signpost, make it for a fork in the road leading to a city; mark out the road for the sword to come to Rabbah of the Ammonites or to Judah and to Jerusalem the fortified.</blockquote>