The story of Adam’s penitence, as told by Tabari, is as follows:--
The moment that Adam fell out of Paradise and touched the ground on the mountains in the centre of Ceylon, he understood in all its magnitude the greatness of his loss and his sin. He remained stupefied with his face on the earth, and did not raise it, but allowed his tears to flow upon and soak into the soil. For a hundred years he remained in this position, and his tears formed a stream which rolled down the mountain, which still flows from Adam’s Peak in the island of Ceylon, and gives their virtue to the healing plants and fragrant trees which there flourish, and are exported for medicinal purposes.
When a hundred years had elapsed, God had compassion on Adam, and sent Gabriel to him, who said, “God salutes thee, O Adam! and He bids me say to thee, Did I not create thee out of the earth by My will? Did I not give thee Paradise to be thine abode? Why these tears and sighs?”
Adam replied, “How shall I not weep, and how shall I abstain from sighing? Have I not lost the protection of God, and have I not disobeyed His will?”
Gabriel said, “Do not afflict thyself. Recite the words I shall teach thee, and God will grant thee repentance which He will accept,” as it is written in the Koran, “Adam learnt of His Lord words; and the Lord returned to Him, for He is merciful, and He returns.” Adam recited these words, and in the joy he felt at the prospect of finding mercy, he wept, and his joyous tears watered the earth, and from them sprang up the narcissus and the ox-eye.
Then said Adam to Gabriel, “What shall I now do?”
And Gabriel gave to Adam wheat-grains from out of Paradise, the fruit of the Forbidden Tree, and he bade him sow it, and he said, “This shall be thy food in future.”
Afterwards, Gabriel taught Adam to draw iron out of the rock and to make instruments of husbandry. And all that Adam sowed sprang up in the self-same hour that it was sown, for the blessing of God was upon it. And Adam reaped and thrashed and winnowed. Then Gabriel bade him take two stones from the mountain, and he taught him with them to grind the corn; and when he had made flour, he said to the angel, “Shall I eat now?” But Gabriel answered, “Not so;” and he showed him how to build an oven of iron. It was from this oven that the water of the deluge at Koufa flowed. He taught him also to make dough and to bake.