Immediately after Moshe instructed Bnei Yisrael regarding the korban Pesach, the Torah tells us, "And Bnei Yisrael went and did as Hashem commanded Moshe and Aharon" (Shemos 12, 28). This communication took place on Rosh Chodesh Nissan. If so, how could they have performed the mitzvah immediately upon being instructed if it was two weeks before the proper time? Rashi explains that although they hadn't actually performed the mitzvah, nevertheless, since they had accepted upon themselves to perform the mitzvah, the Torah considered it as if it had already been completed. An ironclad decision to comply is no different than an actual performance of the commandment.
Therefore, says Rav Wolbe (Shiurei Chumash), Chazal tell us (Berachos 6a) that a person who made up his mind to perform a mitzvah but, due to circumstances beyond his control, was unable to fulfill his desire, is regarded as if he actually succeeded in this endeavor.
Elsewhere, we find another aspect of the magnitude of kabbalah - accepting upon oneself to comply with Hashem's will. Prior to Matan Torah Hashem told Bnei Yisroel, "And now, if you will surely listen to My voice and guard My covenant, you will be for Me like a treasure among all the nations" (Shemos, 19, 5). Rashi, bothered by the seemingly superfluous introduction, "And now," explains that Hashem was conveying to them that if now you (overcome the difficulties and) accept upon yourselves the Torah, henceforth it will be pleasant - because all beginnings are difficult.
Entering the world of Torah study is a transition from a materialistic world into a spiritual world, which is not relegated to the specific time one spends studying the Torah. It affects a person twenty four hours a day seven days a week. However, this transition doesn't always go so smoothly. Many people find that exactly when they open a sefer to learn, they are inundated with a barrage of various thoughts: past memories, future worries, current events and various fantasies. The yetzer hara succeeds in convincing us that concentrating on these thoughts and enjoying these fantasies is a more worthwhile and pleasurable endeavor than focusing on the divrei Torah that lie open before us. How does one combat these unfavorable thoughts? He must make an ironclad kabbalah to devote himself to learning Torah. Once this has been accomplished, he will begin to feel the true pleasure associated with Torah learning and a Torah true life (Alei Shur vol I. pg. 23).
Often, a person encounters difficulties in his avodas Hashem and as a result gives up his worthwhile endeavors. If he would be cognizant of Chazal's axiom that all beginnings are difficult, he would be able to make an ironclad commitment to persevere, which might very well put him over the hump and grant him smooth (and pleasurable) sailing thereafter.