'Solemn' in the Bible

As the holy flock, as the flock of Jerusalem in her solemn feasts; so shall the waste cities be filled with flocks of men: and they shall know that I am the LORD.

But when the people of the land shall come before the LORD in the solemn feasts, he that entereth in by the way of the north gate to worship shall go out by the way of the south gate; and he that entereth by the way of the south gate shall go forth by the way of the north gate: he shall not return by the way of the gate whereby he came in, but shall go forth over against it.