Exodus 10:10

כאשר אשלח אתכם ואת טפכם [MAY THE LORD BE WITH YOU] AS I WILL LET YOU AND YOUR LITTLE ONES GO — even though I were to let go also the flocks and herds as you have said. ראו כי רעה נגד פניכם Understand this as the Targum takes it: See, the evil you are about to do wilt turn against yourself. I have heard a Midrashic explanation: There is a certain star the name of which is רעה “Evil”. Pharaoh said to them, “By my astrological art I see that star rising towards you in the wilderness whither you wish to proceed. It is an emblem of blood and slaughter”. Consequently, when Israel sinned by worshipping the calf and the Holy One, blessed be He, intended to slay them, Moses said in his prayer, (Exodus 32:12) “Wherefore should the Egyptians speak and say, He brought them forth together with רעה (i. e. under the influence of the star רעה); this is, indeed, what he (Pharaoh) has already said, “See, the ‘רעה’ is before you”. At once, “the Lord bethought Himself concerning ‘רעה’”, and He changed the blood of which this star was an emblem to the blood of the circumcision because indeed Joshua had them circumcised. This is the meaning of what is said, (Joshua 5:9). “This day have I rolled from off you the reproach of the Egyptians”, for they said to you. “We see blood impending over you in the wilderness. (Yalkut Shimoni on Torah 1:392; cf. also Rashi on Joshua 5:9.)

וַיֹּ֣אמֶר אֲלֵהֶ֗ם יְהִ֨י כֵ֤ן יְהֹוָה֙ עִמָּכֶ֔ם כַּאֲשֶׁ֛ר אֲשַׁלַּ֥ח אֶתְכֶ֖ם וְאֶֽת־טַפְּכֶ֑ם רְא֕וּ כִּ֥י רָעָ֖ה נֶ֥גֶד פְּנֵיכֶֽם׃

And he said to them, Let the Lord be so with you, as I will let you go, and your little ones: look to it; for evil is before you.