Letters 102.15

Besides, praise is one thing, and the giving of praise another; the latter demands utterance also. Hence no one speaks of “a funeral praise,” but says “praise-giving"—for its function depends upon speech. And when we say that a man is worthy of praise, we assure human kindness to him, not in words, but in judgment. So the good opinion, even of one who in silence feels inward approval of a good man, is praise.

Seneca, Letters to Lucilius 102.15, translated by Richard Mott Gummere