I have a Jewish friend, and sometimes we run into the debate of whether the devil exists or not. I personally believe the devil exists and has some power over the world, and he believes the devil doesn’t exist (or more specifically, doesn’t have an independent existence). He argues that modern conception of the devil and Hell derives from the Catholic Church trying to keep the population in control through fear (e.g. "Do XYZ or else you’re following the devil and will likewise be sent to Hell). I’m not really sure how to respond to his views because Judaism is a religion such that they have closed off the possibility of Original Sin. Therefore, arguing for the devil’s existence is very difficult.
NATURAL IMPULSES from a Jewish perspective
THE good impulse (yetser tov) and the evil impulse (yetser ra) are pictured in Jewish literature as wrestling in perpetual conflict within the heart of man. Satan is usually identified with the yetser ha-ra, the evil impulse. In the book of Job, Satan’s function is described as that of testing the sincerity of men’s characters. In Talmudic literature, Satan’s function is to strengthen man’s moral sense by leading him into temptation. It has been said that every man living shall assuredly meet with an hour of temptation, a certain critical hour, which shall more especially try his mettle.
According to a midrashic statement (Genesis Rabbah 9:9), the existence of the yetser ha-ra in the heart of man and the struggle to overcome it lends high value to the good that emerges from the inner battle. The two conflicting impulses, the good and bad tendencies, are said to be implanted in man as a consequence of his having been formed from the dust and endowed with a soul (Genesis 2:7).
According to rabbinic thinking, the evil impulse is to be found in man at birth; the good impulse begins to develop when he is thirteen years old. The teachings of the Torah are referred to as the antidote to the yetser ha-ra. Similarly, Ben Sira (21:11) states: “The man who keeps the Law controls his natural tendency.”
In commenting on the two yods in the word " ", (Genesis 2:7), the rabbis declare that God created both the yetser tov and the yetser ra (Berakhoth 61a). The command to love God “with all your heart” they interpret to mean “with both your impulses” (Berakhoth Ma), since both human elements can be employed in the service of God. “Were it not for the yetser ha-ra, no man would build a home or get married or follow an occupation” (Genesis Rabbah 9:9). The phrase “very good” (Genesis 1:31) is therefore explained, as alluding to the yetser ha-ra, frequently used in the sense of the productive urge.
Taken from the Encyclopedia of Jewish Concepts
And God saw everything that he had made, and behold, it was very good. And there was evening and there was morning, a sixth day.
Also see this Jewish belief about loving G-d with all your might. Not Satan per se, but the evil inclination.
“And you shall love the L-rd your G-d with all your heart, with all your soul, and with all your might (me’od)” (Deuteronomy 6:4). “With all your heart” – with both your inclinations, with your good inclination and with your evil inclination. “With all your soul” – even to the point that someone takes your life. “With all your meod” – with all your money. Another interpretation: “With all your me’od” – whatever measure (middah) He metes out (moded) to you, thank (modeh) Him exceedingly (me’od me’od).
– Talmud, Berachot 54a