On Sacrifice

In this month of sacrifice, I seek to understand the meaning of sacrifice and why we must sacrifice. Fortunately, answers are everywhere if one but looks.

Shoghi Effendi says the following about the meaning of self-sacrifice:
"Self-sacrifice means to subordinate this lower nature and its desires to the more godly and noble side of ourselves. Ultimately, in its highest sense, self-sacrifice means to give our will and our all to God to do with as He pleases. Then He purifies and glorifies our true self until it becomes a shining and wonderful reality."
I've also heard sacrifice described as giving up something lower for something higher. After my sister had her son (one year and one day ago) and decided to stay home with him, I recall how clearly I began to understand this deeper notion of "sacrifice" as being this notion of choosing something higher.

As to why we must sacrifice, here is some useful guidance from Abdu'l-Bahá:
"Until a being setteth his foot in the plane of sacrifice, he is bereft of every favor and grace; and this plane of sacrifice is the realm of dying to the self, that the radiance of the living God may then shine forth."