Psalms 135:8 Kabbalah

שֶֽׁ֭הִכָּה בְּכוֹרֵ֣י מִצְרָ֑יִם מֵ֝אָדָ֗ם עַד־בְּהֵמָֽה׃

Who smote the first-born of Egypt, Both of man and beast.

Read kabbalistic (mystical) interpretation of Psalms 135:8: and classical mystical sources.