6 I went down to the bottoms of the mountains; the earth with her bars was about me for ever: yet hast thou brought up my life from corruption, O LORD my God.
"the weeds were wrapped about my head. I went down to the bottoms of the mountains; the earth with her bars was about me for ever:" LXX: 'my head has penetrated to the base of mountains; I descended to into the earth whose bars are eternal bonds'. No one doubts that the ocean covered Jonah's head, that he went down to the roots of mountains and came to the depths of the earth by which as bars and columns by the will of God the earthly sphere is supported. This earth about which is said elsewhere, "I consolidated her columns" [Ps. 74:4]. With regard to the Lord Saviour, according to the two editions, this seems to me to be what is meant. His heart and his head, that is the spirit that he thought worthy to take with a body for our safety, went down to the base of the mountains which were covered by waves; they were restrained by the will of God, the deep covered them, they were parted by the majesty of God. His spirit then went down into hell, into those places to which in the last of the mud, the spirits of sinners were held, so too the psalmist says: "they will go down to the depths of the earth, they will be the lot of wolves" [Ps. 62:10.11]. These are the bars of the earth and like the locks of a final prison and tortures, which do not let the captive spirits out of hell. This is why the Septuagint has translated this is a pertinent way: "eternal bonds", that is, wanting to keep in all those whom it had once captured. But our Lord, about which we read these lines of Cyrus in Isaiah: "I will break the bronze bars, I will crack the iron bars" [Is. 45:2], He went down to the roots of the mountains, and was enclosed by eternal bars to free all the prisoners.
Jonah fulfilled a type of our Savior when he prayed from the belly of the fish and said, “I cried for help from the midst of the netherworld.” He was in fact in the fish, yet he says that he is in the netherworld. In a later verse he manifestly prophesies in the person of Christ: “My head went down into the chasms of the mountains.” Yet he was still in the belly of the fish. What mountains encompass you? But I know, he says, that I am a type of him who is to be laid in the sepulcher hewn out of rock. While he was in the sea, Jonah says, “I went down into the earth,” for he typified Christ, who went down into the heart of the earth.
"yet have you brought up my life from corruption, O LORD my God." LXX: 'and from corruption my life comes up to me, O Lord my God.' He says rightly "you have brought up" or "let my life come up from corruption", because it had descended to corruption in hell. This is what the apostles interpret in the fifteenth psalm as prophetic speech of the Lord: "for you will not leave my spirit in hell, and you will not permit your holiness to see the corruption" [Ps. 15:10], given that David is dead and has been buried, but the Saviour's flesh has not known corruption. Others understand that compared to celestial blessing and to the Word of God the body of man is corruption itself, for "it is sown in corruption" [1 Cor. 15:42], and in the psalm one hundred and two, the meaning is applied to a righteous man: "he who cures all illnesses, who has brought his life back from death" [Ps. 102:3.4]. This is why the Apostle says, "O wicked man that I am! Who will deliver me from this body of death?" [Rom. 7:24]. It is called "the body of death", or "body of misery". These people take the text in the sense of their heresy, to see an Antichrist in the place of Christ, and to take the Churches in order to feed a fat stomach and discuss contrary to the flesh living in the flesh. But we, we know that the body taken from the pure Virgin was not the corruption of Christ, but his temple. If we pass then to the thought of the Apostle in Corinthians, where there is the question of a spiritual body, we would say, in removing any appearance of chicanery, that the same body, the same flesh rises again, which has been buried and placed in the soil; but the only thing that changes is the glory, not nature. "for this corruptible being must cover incorruptibility, this mortal being must clothe immortality." [1 Cor. 15:53] When he says "this being" it is almost as if one showed the body by pinching it between two fingers: in which we are born, in which we die, that those who are guilty fear to receive as punishment, that virginity awaits in recompense, that the adulterer fears in punishment. For Jonah, this is how we can understand it: he who would have had to corrupt himself physiologically in the belly of the whale, and get by on the food of beasts and survive by drinking from the veins and arteries, still managed to remain safe and sound. And when he says, "Lord my God", this is a feeling of flattery: he thinks that God, who is common to all, is also common to him, and feels he is his own because of the greatness of his benevolence.
[AD 420] Jerome on Jonah 2:5-6