18 Kislev: Strength From Opposition
STRENGTH FROM OPPOSITION
When people are fighting or wrestling and one begins to gain the upper hand, the other side redoubles its efforts and exerts all its strength to overcome its adversary.
So too, when the forces of good gain the upper hand, the forces of evil exert extra strength... (Tanya, Likkutei Amarim, ch. 28)
The closer we come to Moshiach, the more fiercely the forces of evil oppose our efforts. To overcome this ever-increasing challenge, G-d has given us additional strength and abilities through the essence of the Torah, the teachings of Chassidus.
These teachings reveal how everything is one with G-d. At that point, all opposition automatically disappears. For this reason, Chassidus was only revealed where and when it was truly needed, to complete the process of making the world a home for G-d.
Kuntres Inyanah shel Toras HaChassidus, Appendix I, pp. 27-8