Secrete amicos admone; lauda palam.

Sēcrētē amīcōs admonē; laudā palam.
In secret friends advise; praise openly.

Please note that the translation is word-for-word, which screws up the meaning since English determines meaning from word order and Latin, by and large, does not. A looser English translation making more sense would be: “In secret you should advise friends; you should praise openly.”