Then the Lord spoke to Moses, saying, “Consecrate to Me all the firstborn, whatever opens the womb among the children of Israel, both of man and beast; it is Mine.” (Exodus 13:1-2)
Every Passover, Israel was to commemorate being liberated from Egypt and remember that their firstborn were spared while the firstborn were struck down. In the spirit of thanksgiving for the salvation of their sons and daughters, the firstborn of their children, as well as their livestock, were set apart to God. Today this is still acknowledged in a ceremony called pidyon ha’ben – “redemption of the (firstborn) son.” It is also common in Judaism for firstborn sons to fast on 14 Aviv, which is the day before Passover.
Because the first born of Israel had been redeemed by the blood of a lamb, they were placed in the service of the Creator, initially, as His priests. Considering this special calling, being “firstborn” alludes to spiritual standing within the family. Most importantly, however, in the context of Passover “firstborn” speaks of those who have been redeemed, not necessarily those who were born first. Consider that among notable brothers in Scripture — Cain and Abel, Ishmael and Isaac, Esau and Jacob — it is not the firstborn of the flesh that followed God but the second born. This highlights the fact that the “firstborn” in the eyes of God are those who are in covenant with Him.
We who haver been redeemed by the Blood of the Lamb are regarded as “firstborn” regardless of our position in our earthly families. Consequently, we have been set apart unto God to function as His priests. We have been called from our rebirth in Messiah to be those who are to serve Him in this world and be the light unto the nations. As Peter wrote:
“You are a chosen generation, a royal priesthood, a holy nation, a peculiar people; that ye should show forth the praises of him who has called you out of darkness into his marvelous light.” (1 Peter 2:9)
Blessings and Shalom,