Kohelet Rabbah 3.5

עֵת לְהַשְׁלִיךְ אֲבָנִים, בְּשָׁעָה שֶׁאִשְׁתְּךָ טְהוֹרָה. וְעֵת כְּנוֹס אֲבָנִים, בְּשָׁעָה שֶׁאִשְׁתְּךָ טְמֵאָה. עֵת לַחֲבוֹק, אִם רָאִיתָ כַּתְּ שֶׁל צַדִּיקִים עוֹמְדִים, עֲמֹד וְחַבֵּק וְנַשֵּׁק וְגַפְּפֵם. וְעֵת לִרְחֹק מֵחַבֵּק, אִם רָאִיתָ כַּתְּ שֶׁל רְשָׁעִים, רְחַק מֵהֶם וּמִכַּיּוֹצֵא בָּהֶן.

“A time to cast stones, and a time to gather stones; a time to embrace and a time to refrain from embracing” (Ecclesiastes 3:5). “A time to cast stones,” at a time when your wife is ritually pure; “and a time to gather stones,” at a time when your wife is ritually impure. “A time to embrace” – if you see a group of righteous men standing, stand and embrace, kiss, and caress them; “and a time to refrain from embracing” – if you see a group of wicked men, distance yourself from them and from those like them.