'Solemn' in the Bible

He said to them, "This is that which Yahweh has spoken, 'Tomorrow is a solemn rest, a holy Sabbath to Yahweh. Bake that which you want to bake, and boil that which you want to boil; and all that remains over lay up for yourselves to be kept until the morning.'"

Six days shall work be done, but on the seventh day is a Sabbath of solemn rest, holy to Yahweh. Whoever does any work on the Sabbath day shall surely be put to death.

'Six days shall work be done, but on the seventh day there shall be a holy day for you, a Sabbath of solemn rest to Yahweh: whoever does any work in it shall be put to death.