The captain of my people - This phrase (which does not occur elsewhere in Kings) is remarkable, and speaks for the authenticity of this full report of the actual words of the prophet's message (abbreviated in Isaiah 38:1, etc.). The title, "Captain נגיד nāgı̂yd of God's people," commonly used of David, is applied to Hezekiah, as David's true follower 2 Kings 18:3.

Turn again, and tell Hezekiah the captain of my people,.... The king of them, as the Targum:

thus saith the Lord God of David thy father, I have heard thy prayer, I have seen thy tears; See Gill on Isaiah 38:5.

behold, I will heal thee; instantly, miraculously; and none but God could heal him, his disease being in its kind mortal, and he had been told from the Lord that he should die:

on the third day thou shalt go up unto the house of the Lord: the temple, to give thanks for his recovery; and this he should do on the third day from thence; so soon should he be well, which would show the cure to be miraculous.

Turn again, and tell Hezekiah the captain of my people, Thus saith the LORD, the God of David thy father, I have heard thy {d} prayer, I have seen thy tears: behold, I will heal thee: on the third day thou shalt go up unto the {e} house of the LORD.

(d) Because of his true repentance and prayer, God turned away his wrath.

(e) To give thanks for your deliverance.

20:5 God of, and c. - I am mindful of my promise made to David and his house, and will make it good in thy person. Shalt go - To give me solemn praise for this mercy.

5. Thus saith . the God of David thy father-An immediate answer was given to his prayer, containing an assurance that the Lord was mindful of His promise to David and would accomplish it in Hezekiah's experience, both by the prolongation of his life, and his deliverance from the Assyrians.

on the third day-The perfect recovery from a dangerous sickness, within so short a time, shows the miraculous character of the cure (see his thanksgiving song, Isa 38:9). The disease cannot be ascertained; but the text gives no hint that the plague was raging then in Jerusalem; and although Arab physicians apply a cataplasm of figs to plague-boils, they also do so in other cases, as figs are considered useful in ripening and soothing inflammatory ulcers.

20:1-11 Hezekiah was sick unto death, in the same year in which the king of Assyria besieged Jerusalem. A warning to prepare for death was brought to Hezekiah by Isaiah. Prayer is one of the best preparations for death, because by it we fetch in strength and grace from God, to enable us to finish well. He wept sorely: some gather from hence that he was unwilling to die; it is in the nature of man to dread the separation of soul and body. There was also something peculiar in Hezekiah's case; he was now in the midst of his usefulness. Let Hezekiah's prayer, see Isa 38. interpret his tears; in that is nothing which is like his having been under that fear of death, which has bondage or torment. Hezekiah's piety made his sick-bed easy. O Lord, remember now; he does not speak as if God needed to be put in mind of any thing by us; nor, as if the reward might be demanded as due; it is Christ's righteousness only that is the purchase of mercy and grace. Hezekiah does not pray, Lord, spare me; but, Lord, remember me; whether I live or die, let me be thine. God always hears the prayers of the broken in heart, and will give health, length of days, and temporal deliverances, as much and as long as is truly good for them. Means were to be used for Hezekiah's recovery; yet, considering to what a height the disease was come, and how suddenly it was checked, the cure was miraculous. It is our duty, when sick, to use such means as are proper to help nature, else we do not trust God, but tempt him. For the confirmation of his faith, the shadow of the sun was carried back, and the light was continued longer than usual, in a miraculous manner. This work of wonder shows the power of God in heaven as well as on earth, the great notice he takes of prayer, and the great favour he bears to his chosen.