Lamb Selection Day is closely connected with Yom haKippurim (Day of Atonement). Both occur on the 10th day of their respective months: first month for Lamb selection day and seventh month of Yom Kippur.
And the words of the herald for the Mashiakh (Messiah), Yokhanan the Immerser (John the Baptist), that Yeshua was “the Lamb of God Who takes away the sins of the world” (Jn. 1:29) further connects these two memorials of God’s salvation plan.