Zeal without knowledge is the sister of folly.

Understand the thought

Meaning in plain English

Enthusiasm without relevant knowledge can lead to foolish choices. Commitment is more useful when you understand what the task requires and remain willing to correct an unsuitable approach.

What the words are saying

The saying personifies zeal without knowledge as a close relative of folly. Its concern is the gap between wanting strongly to act and knowing enough to act well. This is substantially the same warning as the related entry that calls uninformed zeal frenzy; the different image does not create a new historical principle. The proverb need not discourage beginners, because learning can accompany a supported first step. The useful question is what information or guidance would make the effort appropriate. Praising commitment by itself can miss whether the proposed action actually serves the purpose and those affected by it.

Everyday example

A keen volunteer asks how fragile records should be handled before offering help, recognising that careful guidance makes willingness more useful.

When to use it

Use it when willingness needs information or suitable guidance to become effective.

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