It would appear that "the foundations of heaven" and "the foundations of the wall of the city" are the same thing. Are the firmament and the foundations of heaven the same thing?
Firmament 10
Firmament 9
And they that be wise shall shine as the brightness of the firmament; and they that turn many to righteousness as the stars for ever and ever.
Firmament 8
Then I looked, and, behold, in the firmament that was above the head of the cherubims there appeared over them as it were a sapphire stone, as the appearance of the likeness of a throne.
Firmament 7
And above the firmament that was over their heads was the likeness of a throne, as the appearance of a sapphire stone: and upon the likeness of the throne was the likeness as the appearance of a man above upon it.
Firmament 6
And the likeness of the firmament upon the heads of the living creature was as the colour of the terrible crystal, stretched forth over their heads above.
Firmament 5
Praise ye the LORD. Praise God in his sanctuary: praise him in the firmament of his power.
Firmament 4
The heavens declare the glory of God; and the firmament sheweth his handywork. Day unto day uttereth speech, and night unto night sheweth knowledge.
Firmament 3
According to the context of our verse the open firmament is where birds fly, so it's the atmosphere or sky. We can consider it to be the first of three heavens.
Firmament 2
And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years:
The Firmament Rabbit Trail
One of our favorite ways to study the Bible is to follow a doctrine through from the first time it's mentioned to the last. This is a great way to develop understanding of the doctrine in the broad narrative of scripture.