How we have a Yetzer Hara

וַיִּהְיוּ שְׁנֵיהֶם עֲרוּמִּים, הָאָדָם וְאִשְׁתּוֹ וְלֹא יִתְבֹּשָׁשׁוּ

" And they were both naked, the man and his wife, and were not ashamed."

ולא יתבוששו: שלא היו יודעים דרך צניעות להבחין בין טוב לרע, ואף על פי שנתנה בו דעה לקרות שמות, לא נתן בו יצר הרע עד אכלו מן העץ ונכנס בו יצר הרע וידע מה בין טוב לרע

and (they) were not ashamed: for they did not know the way of modesty, to distinguish between good and evil (Gen. Rabbah) (Targum Yerushalmi), and even though knowledge was granted him to call [all the creatures] names, he was not imbued with the evil inclination until he ate of the tree, and the evil inclination entered into him, and he knew the difference between good and evil. (Rashi)

It would appear from Rashi's words that prior to eating the forbidden fruit, he had no Evil Inclination. This being the case, how is it that Adam was capable of performing a sin, breaking God's commandment, seeing as he had no inclination to do so?

Furthermore, Chazal teach us that the purpose of creation was to partake in the service of God, by battling the Evil Inclination that tries to prevent one from fulfilling hsi duties and overcoming it. Again, this being the case, what function would the creation have served if there was no Evil Inclination, as we have understood Rashi to have said.

R' Chaim Volozhin explains that certainly Adam had all the faculties, notably free will, instilled within him before the sin, to enable to him to do as he saw fit. What he didn't have, was an internal urge to sin or do evil, rather, this Evil Inclination, Satan, was an external being to Adam, and it had to physically manifest itself as the snake to ensnare Adam and Eve, unlike today, where this battle is an internal battle, choice, decision.

If we review the original quote from Rashi, it would seem that he implies this:

"לא נתן בו יצר הרע עד אכלו מן העץ ונכנס בו יצר הרע"

that the Evil Inclination only became an innate thing in man once he consumed the fruit and it became part of him.

Geshmack !