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."
"And he that believeth on him shall not be put to shame ... In view here is the eternal shame which attaches to the Jewish nation for the rejection of the Messiah, the shame being simply this: the very Christ whom they contemptuously rejected was chosen by God to be the head of the new Israel; and the Father gave him "a name which is above every name"  (Philippians 2:9). On the other hand, fidelity to Christ brings honor and glory to the believer, since he partakes of the honor and glory of Christ himself.