Sirach 6:6-8

Revised Standard Version

⁶ Let those that are at peace with you be many,
    but let your advisers be one in a thousand.
⁷ When you gain a friend, gain him through testing,
    and do not trust him hastily.
⁸ For there is a friend who is such at his own convenience,
    but will not stand by you in your day of trouble.