This obscure phrase plays itself out in The Trial of Impeachment of Levi Hubbell, Judge of the Second Judicial Circuit. The trial was held in the Wisconsin Senate in June of 1853. The proceedings allow you to read the debate about the meaning of it being time to fish or cut bait which was, at that time, an unfamiliar phrase. In that context, the somewhat archaic term “enjoin” is clarified: if you state your intention, you should follow it up or make it clear you won't follow it up. The same meaning is reflected in the phrase “sh... or get off the pot.” The aphorism’s original meaning was not simply about making a choice, as it is often used, but rather a direction to act upon your promises.

Matthew 20:22
But Jesus answered, "You do not know what you are asking.
Are you able to drink the cup that I am to drink?"

The Gospels are full of examples of Jesus asking his followers to take their commitment seriously. Both Mark and Matthew report that James and John come to Jesus wanting to have the honour of sitting at his right and his left in “His glory.” In Matthew’s Gospel (22:20), it is the “mother of Zebedee's sons” who asks the question. In Mark (10:35), it is James and John themselves who ask for the prominent spots. In each case, Jesus responds with a question that almost certainly points to his crucifixion. He is saying, if you want to be close to me, you need to “fish or cut bait” in the sense that their request to sit in glory implies a commitment to follow wherever Jesus’ path leads. That commitment will soon ask them to follow with related choices and actions, commitments and risk.