2 Chronicles 30:13

And there assembled at Jerusalem much people to keep the feast of unleavened bread in the second month, a very great congregation.

Cross-reference

2 Chronicles 30:2 Historical context

2 Chronicles 30:2 explains why they gathered — the assembly had decided to keep Passover in the second month, which this verse describes.

2 Chronicles 7:8 also uses 'very great congregation' for Solomon's feast, directly paralleling this assembly.

1 Kings 8:65 describes Solomon's great feast with all Israel, paralleling the great congregation for Hezekiah's Passover.