John Gill Commentary Job 38:6

"Whereupon were the foundations thereof fastened? Or who laid the corner-stone thereof," — Job 38:6 (ASV)

Whereupon are the foundations thereof fastened ?
&c.] Or the pillars of it, as Ben Gersom interprets it; see (Psalms 75:3) ; and which Aben Ezra understands of the mountains: but be they what they may, on what can they be fastened or sunk into, when the earth hangs on nothing, and there is nothing visible to support it, nothing but the mighty hand of God?

or who laid the corner stone thereof ?
which unites, cements, and keeps the fabric together, and is the ornament and beauty of it; but who can tell what that is? Aben Ezra interprets it of the point or centre of the earth.