Rosh HaShannah is the Feast of Trumpets, and literally Yom Teruah, Day for Blowing the Shofar. What is the significance of the shofar blasts? It is a call to return—a call for repentance.
The betrothal of Israel to Adonai was interrupted by the maiden’s unfaithfulness. This is the message of the Prophets. Consider Jeremiah 31:31-34 which promises the New Covenant:
“Behold, days are coming,” declares the LORD, “when I will make a new covenant with the house of Israel and with the house of Judah, not like the covenant which I made with their fathers in the day I took them by the hand to bring them out of the land of Egypt, My covenant which they broke, although I was a husband to them,” declares the LORD. “But this is the covenant which I will make with the house of Israel after those days,” declares the LORD, “I will put My law within them and on their heart I will write it; and I will be their God, and they shall be My people. “They will not teach again, each man his neighbor and each man his brother, saying, ‘Know the LORD,’ for they will all know Me, from the least of them to the greatest of them,” declares the LORD, “for I will forgive their iniquity, and their sin I will remember no more.”
Here the Lord presents Himself as Israel’s Husband (or Husband to be, for in ancient times betrothal was legally binding even as marriage was) and describes Israel’s unfaithfulness to Him.
When a betrothed maiden is unfaithful to her betrothed, he has every right to “put her away,” that is, to give her an annulment of the betrothal contract. In such a case, the bride price returns to the would-be groom, and the bride is disgraced. The groom is not required to do this, mind you, but he may if he so desires. The example that immediately comes to mind, of course, is that of Mary and Joseph.
What Rosh HaShannah tells us is that, while Israel played the part of the unfaithful, betrothed maiden, God, her betrothed, calls her back—calls her to repentance. Her waywardness is grievous, but He is willing to forgive, and even to heal, but she must return—she must repent of her evil deeds. The rightful Husband, the one who has signed the ketubbah with His own finger, calls His betrothed wife back to Him—back to faithfulness to the betrothal agreement, the Torah.
Thus, Rosh HaShannah also emphasizes God’s rightful ownership of His bride. The Day commemorates His sovereign kingship, and His right to possess His betrothed. In calling her back to Him, He re-establishes His rightful place beside her.