The Spiritual Battle

It is with the service of G‑d just as it is with a victory over a physical opponent; for instance, two people who wrestle with each other, each striving to fell the other.

If one of them is lazy and sluggish he will easily be defeated and will fall, even if he be stronger than the other, since his laziness and sluggishness prevent him from revealing his strength.

ככה ממש בנצחון היצר

Similarly with the conquest of one’s evil nature.

- Tanya / Jewish Mysticism