בָּרוּךְ אַתָּה יְהֹוָה אֱלֹהֵֽינוּ מֶֽלֶךְ הָעוֹלָם אֲשֶׁר קִדְּ֒שָֽׁנוּ בְּמִצְוֹתָיו וְצִוָּנוּ
לַעֲסֹק בְּדִבְרֵי תוֹרָה: וְהַעֲרֶב נָא יְהֹוָה אֱלֹהֵֽינוּ אֶת־דִּבְרֵי תוֹרָתְךָ בְּפִֽינוּ וּבְפִי עַמְּךָ בֵּית יִשְׂרָאֵל.
Blessed are You, Hashem, our God, King of the Universe, Who sanctified us with His commandments and commanded us to be engrossed in the words of Torah. Hashem, our God, please make the words of Your Torah pleasant in our mouths and the mouths of Your people, Israel.
We ask Hashem in the morning to make Torah sweet and pleasant. But first, we make a Bracha "לַעֲסֹק בְּדִבְרֵי תוֹרָה," the prerequisite to tasting the Torah's sweetness can only come from engrossing ourselves in its study.
The Midrash compares Torah to oil, which starts sour (like an olive) before becoming sweet. The Chazon Ish teaches that those who have spent many uninterrupted hours learning Torah won't question this sweetness. (ספר אש תמיד page 152-162)