Beraishit 17.10- בראשית

 The Commandment of Circumcision attaches the physical (1) to the metaphysical (8). This is proven from the following gematriot of the verse.

10.’This is My Covenant, which you shall keep, between Me and you and your offspring after you shall circumcise every male among you-זֹאת בְּרִיתִי אֲשֶׁר תִּשְׁמְרוּ בֵּינִי וּבֵינֵיכֶם וּבֵין זַרְעֲךָ אַחֲרֶיךָ הִמּוֹל לָכֶם כָּל זָכָר (3739+13 words=3752=17=8).

Rashi comments that the command is for all time-then and the future-all generations.

You shall circumcise!

הִמּוֹל

81

You shall circumcise every male among you

הִמּוֹל לָכֶם כָּל זָכָר

 1008

Every male

כָּל זָכָר

722+2 words=18