Psalms 137:9 Midrash

אַשְׁרֵ֤י ׀ שֶׁיֹּאחֵ֓ז וְנִפֵּ֬ץ אֶֽת־עֹ֝לָלַ֗יִךְ אֶל־הַסָּֽלַע׃

Happy shall he be, that taketh and dasheth thy little ones Against the rock.

Read midrashic interpretation of Psalms 137:9: and classical rabbinic exegesis.