'Seven' in the Bible

On the day after the festival ended, they convened a solemn assembly, because they had been dedicating the altar for seven days and observing the festival for seven days.

Seven years later, Jehoiada mustered up some courage and made a deal with the officers who commanded units of hundreds of soldiers, including Jehoram's son Azariah, Jehochanan's son Ishmael, Obed's son Azariah, Adaiah's son Maaseiah, and Zichri's son Elishaphat.

Joash was seven years old when he began his reign, and he reigned forty years in Jerusalem. His mother's name was Zibiah. She was from Beer-sheba.

where they brought seven rams, seven lambs, and seven male goats for a sin offering on behalf of the kingdom, the Holy Place, and Judah. He ordered that the priests, as descendants of Aaron, place the offerings on the LORD's altar.

The Israelis who were present in Jerusalem observed the Festival of Unleavened Bread for seven days with immense gladness, and the descendants of Levi and priests praised the LORD throughout each day, singing mightily to the LORD.

Hezekiah encouraged all the descendants of Levi who demonstrated significant insight in their service to the LORD, so they all participated in the festival meals for seven days, all the while sacrificing peace offerings and giving thanks to the LORD God of their ancestors.

After this, the whole assembly agreed to celebrate for another seven days, and so they did and they were very happy to do so!

The Israelis who were present celebrated the Passover that day, as well as the Festival of Unleavened Bread for seven days.