Every "may be" hath a "may not be."

Understand the thought

Meaning in plain English

An uncertain outcome can fail to happen as well as happen. The saying balances hope with the alternative possibility, without claiming that the two outcomes are equally likely or that uncertainty makes preparation pointless.

What the words are saying

The phrase may be is answered by may not be, making the uncertainty explicit in both directions. A useful reading prevents a possible benefit from becoming a settled assumption merely because it is attractive. Ask what is known, what remains undecided and what would be done if the hoped-for result does not occur. The saying does not calculate a probability, and some possibilities have much stronger support than others. It also need not forbid commitment under uncertainty. Its point is to describe the situation honestly and make a plan that recognises the alternative rather than silently treating hope as confirmation.

Everyday example

A group prepares two programme outlines while waiting to learn whether a guest speaker can attend, rather than publishing the preferred version as confirmed.

When to use it

Use it when a possibility is being treated as a certainty.

Agent-assisted editorial interpretation. This explains the words; it does not by itself verify their author or earliest origin.