'Itself' in the Bible

There is nothing reliable in what they say;Their inward part is destruction itself.Their throat is an open grave;They flatter with their tongue.

And when he comes to see me, he speaks falsehood;His heart gathers wickedness to itself;When he goes outside, he tells it.

The earth quaked;The heavens also dropped rain at the presence of God;Sinai itself quaked at the presence of God, the God of Israel.