Kohelet Rabbah 7.29

לְבַד רְאֵה זֶה מָצָאתִי אֲשֶׁר עָשָׂה הָאֱלֹהִים אֶת הָאָדָם יָשָׁר, יָשָׁר הָיָה, שֶׁנֶּאֱמַר: אֲשֶׁר עָשָׂה הָאֱלֹהִים אֶת הָאָדָם יָשָׁר, וּכְתִיב (בראשית ג, כב): הֵן הָאָדָם הָיָה כְּאַחַד מִמֶּנּוּ, כְּאֶחָד מִמַּלְאֲכֵי הַשָּׁרֵת, וְכֵיוָן שֶׁנַּעֲשׂוּ שְׁנַיִם, וְהֵמָּה בִקְשׁוּ חִשְׁבֹנוֹת רַבִּים.

“But, see, this I have found: God made man upright, but they have sought many schemes” (Ecclesiastes 7:29). “But, see, this I have found: God made man upright” – he was upright, as it is stated: “God made man upright,” and it is written: “Behold, man has become like one of us” (Genesis 3:22) – like one of the ministering angels. When they became two, “but they have sought many schemes.”