Reference for Proverbs 27:19

כַּ֭מַּיִם הַפָּנִ֣ים לַפָּנִ֑ים כֵּ֤ן לֵֽב־הָ֝אָדָ֗ם לָאָדָֽם׃

As in water face answereth to face, So the heart of man to man.

BDB