I will multiply thy seed as the stars of the heaven, and as the sand which [is] upon the sea shore;

Most readers of Scripture view this as prophecy for modern Israelites.  But when did the Israelites really believe that their numbers were "as the sand which is upon the sea shore"?  We see from the following verses that Israelites considered themselves to be that numerous at the time of Samuel and of Solomon:

2Sa 17:11 Therefore I counsel that all Israel be generally gathered unto thee, from Dan even to Beer-sheba, as the sand that is by the sea for multitude; and that thou go to battle in thine own person.

1Ki 4:20 Judah and Israel were many, as the sand which is by the sea in multitude, eating and drinking, and making merry.

This is also a phrase which is used in reference to the enemies of the Israelites:

Jos 11:4 And they went out, they and all their hosts with them, much people, even as the sand that is upon the sea shore in multitude, with horses and chariots very many.

 

Gen 22:17 That in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which [is] upon the sea shore; and thy seed shall possess the gate of his enemies;

Gen 22:18 And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.

Gen 32:12 And thou saidst, I will surely do thee good, and make thy seed as the sand of the sea, which cannot be numbered for multitude.

Gen 32:13 And he lodged there that same night; and took of that which came to his hand a present for Esau his brother;