Does Hashem reward you for keeping negative mitzvot or only punishes for trangressions?
רַבִּי שִׁמְעוֹן אוֹמֵר, מִמְּקוֹמוֹ הוּא לָמֵד, שֶׁנֶּאֱמַר (ויקרא יח) וְנִכְרְתוּ הַנְּפָשׁוֹת הָעֹשֹׂת וְגוֹ', וְאוֹמֵר (שם) אֲשֶׁר יַעֲשֶׂה אֹתָם הָאָדָם וָחַי בָּהֶם. הָא, כָּל הַיּוֹשֵׁב וְלֹא עָבַר עֲבֵרָה, נוֹתְנִין לוֹ שָׂכָר כְּעוֹשֶׂה מִצְוָה.
Rabbi Shimon says, We [do not need the kal vachomer to learn this] can learn it from its place [context], as it says "They [the person performing incest] will have their soul cut off" (Leviticus 18:5) and it says [at the beginning of the verse] "Which man shall carry out and by which he shall live." From this [we learn] that whoever just sits and commits no sin, is given a reward like the one who fulfilled a commandment.
Rashi in Deut 12:25 does imply that one would be rewarded for abstaining from a negative commandment even when there is no desire. The Torah provides a reward for not eating blood even though one might be repulsed by the thought of eating blood, thus we see reward for abstention even when there is no desire. However, This may only be true when one is presented with a real opportunity, such as prior to salting after slaughter.
On the simplest level, it’s worth considering this question in the context of the seven universal commandments of Noach which are incumbent upon all mankind.
According to many, those seven commandments are all negative. A Gentile who keeps them is judged righteous and receives a reward of *Olam **HaBa*.
It is emphasized that the Olam HaBa which they receive is categorically different from that which a Jew receives. This is understood from the idea that Jews are commanded both negative and positive mitzvot, while gentiles are only commanded negative mitzvot.
The 248 positive commandments relate to the 248 bones of the physical body.
Thus, the reward for Jews is also physical and pertains to their body.
The negative commandments pertain to the soul and spiritual reward.
And this explains why the Olam HaBa of Jews and Gentiles is different. Their reward is only spiritual and pertains to their soul.
Jews receive reward for the service of their soul through their negative commandments and also the service of their bodies through the fulfillment of their positive commandments.