וַיְדַבֵּ֥ר מֹשֶׁ֛ה כֵּ֖ן אֶל־בְּנֵ֣י יִשְׂרָאֵ֑ל וְלֹ֤א שָֽׁמְעוּ֙ אֶל־מֹשֶׁ֔ה מִקֹּ֣צֶר ר֔וּחַ וּמֵעֲבֹדָ֖ה קָשָֽׁה׃ (פ)
And Moses spoke so unto the children of Israel; but they hearkened not unto Moses for impatience of spirit, and for cruel bondage.
Read kabbalistic (mystical) interpretation of Exodus 6:9: and classical mystical sources.