In those days Hezekiah was stricken with a terminal illness. ¹  He prayed to the Lord, who answered him and gave him a sign confirming that he would be healed. ² 

So when the envoys arrived from the Babylonian officials to visit him and inquire about the sign that occurred in the land, ¹  God left him alone to test him, in order to know his true motives. ²