| "And you shall love HaShem your G-d with all your heart, with all your soul, and with all your might." The Sages derive from the phrase, "and with all your might": "whether HaShem sends a person happy times or difficult times, he must accept it in happiness." How is it possible to accept difficult times in happiness? HaShem sends every soul to this world to be "tested." For example, the poor man's test is to endure his challenges with trust in HaShem, while the rich man's test is to share his wealth with the poor. The tests that HaShem sends each person is uniquely designed as a means for his self-improvement. However, since each test is custom made for each soul, it would be very burdensome for someone to withstand the trials of his friend. Since, HaShem only sends us tests that we can pass, hence our Sages teach us to "accept our situation with happiness." Even if our test is greatly challenging, we must keep the faith, because HaShem sent us this test for our benefit and growth.
HaShem sends us tests perfectly designed for our self-improvement, which we can definitely pass. Therefore, since each test is for our benefit, it makes perfect sense to accept every test with happiness.
Envision a great warrior, who always chooses the toughest battles, in order to show his strength and bravery. It is the same in our "spiritual battle" with the negative impulse. If you meet a situation which requires great effort and bravery, and you master the moment, this reveals your great trust in HaShem. Even more, HaShem will count you as one "who loves HaShem." (Based on the commentary of the Chofetz Chaim) | 
