Why is the binding of Isaac read on Rosh Hashanah?

A day for remembering

The Torah never calls the day Rosh Hashanah, and it never connects it with Isaac. It gives a date and a sound.

In the seventh month, on the first day of the month, there shall be a solemn rest for you, a memorial of blowing of trumpets, a holy convocation.

In Hebrew the memorial is zikhron teruah, a remembrance made with a blast. Numbers 29:1 calls it simply “a day of blowing of trumpets.” The name Rosh Hashanah, “head of the year,” comes later, from the Mishnah, the rabbinic law code compiled around AD 200, which gives a whole tractate to the day. That leaves a question: what is to be remembered, and by whom? The rabbis found the answer on a mountain in the land of Moriah.

Two days, two sons

The Talmud fixes the readings (Megillah 31a), and synagogues still follow it.

• First day. Genesis 21: “Yahweh visited Sarah as he had said” (21:1), and Isaac is born. The prophetic reading is the story of Hannah, who prays for a son, and “Yahweh remembered her” (1 Samuel 1:19).
• Second day. Genesis 22, the Akedah, the binding. Abraham takes Isaac up the mountain, binds him on the altar and is stopped by a voice from heaven. The prophetic reading is Jeremiah 31, where God says of Ephraim, “I still earnestly remember him” (31:20).

The Talmud adds that Sarah, Rachel and Hannah were all remembered on Rosh Hashanah, the day each one’s long wait for a child came to an end (Rosh Hashanah 11a). The first day is about children given. The second is about a child given back.

Why a ram’s horn

Abraham lifted up his eyes, and looked, and saw that behind him was a ram caught in the thicket by his horns. Abraham went and took the ram, and offered him up for a burnt offering instead of his son.

The Talmud draws a straight line from that thicket to the synagogue. Rabbi Abbahu asks why the shofar is a ram’s horn, and answers in God’s voice: blow before me with a ram’s horn, so that I will remember for you the binding of Isaac son of Abraham, and count it as if you had bound yourselves before me (Rosh Hashanah 16a).

Jewish law follows the story. The Mishnah accepts the horns of several animals but rejects a cow’s (Rosh Hashanah 3:2). The Talmud explains why: a cow recalls the golden calf, and the old accuser cannot stand up as the defender (Rosh Hashanah 26a). Later codes prefer a ram’s horn, and a curved one (Shulchan Aruch, Orach Chayim 586:1). A midrash even follows the ram’s two horns. The left one sounded at Sinai, where the trumpet “grew louder and louder” (Exodus 19:19). The right one is kept for the day when “a great trumpet will be blown” (Isaiah 27:13).

The prayer that asks God to remember

The additional service of Rosh Hashanah has a section called Zikhronot, Remembrances, built from Bible verses in which God remembers. “God remembered Noah” (Genesis 8:1) is one. “I will remember my covenant with Jacob, my covenant with Isaac, and also my covenant with Abraham” (Leviticus 26:42) is another. The section ends by asking God to remember the binding of Isaac in mercy for his descendants. Then the shofar sounds.

Other reasons were added over the centuries. In the tenth century Saadia Gaon counted ten reasons for blowing the shofar, and the Akedah is one of them. Maimonides heard a wake-up call in it, telling sleepers to rise and look at their deeds (Laws of Repentance 3:4). Christians and Muslims remember the same test in their own ways (which son was it?). Ten days after Rosh Hashanah comes Yom Kippur, and its afternoon reading is the book of Jonah.