Albert Barnes Commentary Isaiah 37:1

"And it came to pass, when king Hezekiah heard it, that he rent his clothes, and covered himself with sackcloth, and went into the house of Jehovah." — Isaiah 37:1 (ASV)

When King Hezekiah heard it – He heard the account of the words of Rabshakeh (Isaiah 36:22).

That he tore his clothes – (See the note at Isaiah 36:22).

He covered himself with sackcloth – (See the note at Isaiah 3:24).

And went into the house of the Lord – He went up to the temple to spread out the case before Yahweh (Isaiah 37:14).

This was in accordance with the usual habit of Hezekiah, and it teaches us that when we are surrounded by difficulties or danger, and when the name of our God is blasphemed, we should go and spread out our feelings before God and seek His aid.