All Christians are spiritually “firstborns” and have a right to a firstborn double portion!
Hebrews 12:23

WHO firstborns are responsible for

Look up to God but don’t forget to look down, Luke 10:30-37

As a firstborn I am responsibility for…
Those younger than me
Those younger than me in faith
Those who are not yet following Jesus

The spirit of the firstborn must fill us before the blessing of the firstborn falls upon us. And the spirit of the firstborn is “I am responsible for God’s children, not just those who are in church but those who are out in the world and aren’t saved yet.” Jimmy Evans

HOW firstborns are responsible
Share, bless, give, etc., especially to those who have yet to receive their double portion
Be an example, a role model, someone to follow, perhaps even look up to
Teach, instruct, mentor, encourage, challenge, disciple – Titus 2:4-6
Lead spiritually: in prayer, pointing the way, encouraging into the Bible, small groups

Ways a true firstborn behaves (note Miriam in Exodus 2):
Steps up, no matter the situation
Never says, “it’s not my job”
Walks into the room looking, paying attention, noticing…

WHEN I am responsible…

Responsibility is not a call of convenience

Now, note this pattern in the Bible

Exodus 4:22, Jeremiah 31:9

But neither Israel nor Ephraim was really firstborn – what’s going on here?

There is a pattern in biblical history of what happens when we are only interested in the blessing instead of the responsibility.

Esau wanted the privilege without the responsibility, but it doesn’t work that way. He only appreciated the blessing after he had lost it and when it was too late to recover it.
Genesis 25:29-34
Genesis 27:34
Genesis 32:24-30

Esau chose lunch. Jacob wrestled with God all night for a true blessing!

Reuben chose sin
Genesis 35:22

Now Reuben, you can’t find a noteworthy man among his descendants, in all of scripture.
Tom Martincic

But men like Jacob, Joseph, Ephraim, Judah, Moses all received blessings, none of whom are firstborn!

The firstborn has a right to the blessing, but can choose to give up those blessings
We can choose the “stuff” like Esau, Reuben, even Adam.
Or we can choose the best and the “stuff” will follow!

Matthew 6:33
That’s what happened for Jacob, Joseph, Ephraim, Judah and Moses!

If you’re going to have the firstborn blessing you have to take responsibility for His family.
Jimmy Evans

When I get to heaven Jesus is going to look over my shoulder and say, Well done good and faithful servant but who did you bring with you?”
Nick Vujicic

So, specifically, who are you “responsible” for?