Sirach 18:19

19 Learn before thou speak, and use physick or ever thou be sick.

Sirach 18:19 In-Context

17 Lo, is not a word better than a gift? but both are with a gracious man.
18 A fool will upbraid churlishly, and a gift of the envious consumeth the eyes.
19 Learn before thou speak, and use physick or ever thou be sick.
20 Before judgment examine thyself, and in the day of visitation thou shalt find mercy.
21 Humble thyself before thou be sick, and in the time of sins shew repentance.

The Brenton translation of the Septuagint is in the public domain.