Mind agitated, wavering,
hard to guard and hard to check,
one of wisdom renders straight
as arrow-maker a shaft.

Explanation: In the Dhammapada there are several references to the craftsmanship of the fletcher. The Buddha seems to have observed the process through which a fletcher transforms an ordinary stick into an efficient arrow-shaft. The disciplining of the mind is seen as being a parallel process. In this stanza the Buddha says that the wise one straightens and steadies the vacillating mind that is difficult to guard, like a fletcher straightening an arrow-shaft.

Source: BuddhaNet