Luke 2:43

When the feast ended they started the return trip. Jesus remained behind in Jerusalem and his parents did not know this.

Exodus 12:15

You will eat unleavened bread for seven days. The first day you shall remove leaven from your houses. Whoever eats anything leavened from the first day until the seventh day will be cut off from Israel.

2 Chronicles 25:17

After receiving counsel from his advisers, King Amaziah of Judah sent messengers to King Jehoash, son of Jehoahaz and grandson of Jehu of Israel, to declare war on Israel.

2 Chronicles 30:21-23

Thus the Israelites in Jerusalem celebrated the Festival of Unleavened Bread for seven days with great joy. Each day the Levites and priests praised Jehovah in song. They played Jehovah's instruments loudly.

Treasury of Scripture Knowledge

Summary

And when they had fulfilled the days, as they returned, the child Jesus tarried behind in Jerusalem; and Joseph and his mother knew not of it.

Bible References

General references

2 Chronicles 30:21
Thus the Israelites in Jerusalem celebrated the Festival of Unleavened Bread for seven days with great joy. Each day the Levites and priests praised Jehovah in song. They played Jehovah's instruments loudly.
2 Chronicles 25:17
After receiving counsel from his advisers, King Amaziah of Judah sent messengers to King Jehoash, son of Jehoahaz and grandson of Jehu of Israel, to declare war on Israel.