Because it is contained in Scripture, "Behold, I lay in Zion a chief cornerstone, chosen, and precious: He who believes in him will not be disappointed."
The manner of restoration he thus describes, “I will lay in Sion a stone.” We hence learn that there is no building up of the Church without Christ; for there is no other foundation but he, as Paul testifies, (1 Corinthians 3:11.) This is no matter of wonder, for all our salvation is found only in him. Whosoever, then, turns away from him in the least degree, will find his foundation a precipice. 