What is the church? In Covenant.

What is the church?  And what can we liken it to in Genesis 15?

"And he said to him, “Take for me a three-year-old heifer, and a three-year-old female goat, and a three-year-old ram, and a turtledove and a young pigeon.” And he took for him all these and cut them in pieces down the middle. And he put each piece opposite the other, but the birds he did not cut. And the birds of prey came down on the carcasses, but Abram drove them away. And it happened, as the sun went down, then a deep sleep fell upon Abram and, behold, a great terrifying darkness fell upon him." 
"And after the sun had gone down and it was dusk, behold, a smoking firepot and a flaming torch passed between those half pieces. On that day Yahweh made a covenant with Abram..."

God promises.  God swears by himself for there is no higher authority to swear by.  God, who's yes is yes and no is no and has no reason to swear by anything, makes vows to us, his people.  Why?

"For people swear by what is greater than themselves, and the oath for confirmation is the end of all dispute for them. In the same way God, because he wanted to show even more to the heirs of the promise the unchangeableness of his resolve, guaranteed it with an oath, in order that through two unchangeable things, in which it is impossible for God to lie, we who have taken refuge may have powerful encouragement to hold fast to the hope set before us, which we have like an anchor of the soul, both firm and steadfast..." (Heb 6)

Okay, so what does God promise?  What has God vowed to His church?  Never mind that, just yet.  Bask, meditate, reel from the staggering fact that He does!