Rabbi Nachman teaches,
When a person is in special need of G-d’s love, G-d sends him an opportunity to show love to someone else. This is what makes it possible for G-d’s love to be channeled to the person himself, because “Everyone who shows love for G-d’s creatures is himself shown love” ( Shabbat 151b) . Thus it is written: “And He will give you love [i.e. He will give you the opportunity to show love to someone else] and [then] He will show you compassion” (Deuteronomy 13:18 ) .
A person’s ability to show love depends on his level of G-dly awareness. One who has G-dly awareness will have compassion. For anger, the opposite of compassion, is rooted in foolishness: “Anger rests in the bosom of fools” ( Ecclesiastes 7:9) . Accordingly our Rabbis said, “It is forbidden to show compassion to anyone who lacks understanding” ( Berachot 33a) . This is because a person who lacks understanding is necessarily lacking in compassion (since “anger rests in the bosom of fools”). This is why it is forbidden to have compassion on him, because “Everyone who shows love for G-d’s creatures is himself shown love”, but if a person lacks compassion, it is impossible to have compassion on him.
Thus one who is in need of G-d’s compassion must show compassion for others, and this depends on deepening his G-dly understanding.
Likutey Moharan I, 119
With permission taken over from: Daily Dose Of Rabbi Nachman