R. Johanan b. Zakai was asked by R. Eleazar b. Arach permission to expound some of the mysteries of the creation (Ma’ase Merkaba). R. Johanan dismounted from his ass, as angels might be present, and sat on a stone under an olive tree. Then Eleazar began to expound them and fire descended from heaven and the trees broke forth into song. R. Johanan kissed R. Eleazar on the head and said “Blessed be the Lord, God of Israel, who gave to Abraham our father, a son like unto thee/’ R. Joshua and R. Jose, the priest, when they heard of it, tried to do the same. It happened to be the 17th day of Tammuz and the heavens became clouded and the ministering angels gathered there, like people who come to a wedding feast. This was told by the two rabbis named to R. Johanan and he said, “Blessed are ye and blessed are mine eyes which have seen in a dream you and me sitting on Mount Sinai and have heard a voice from heaven saying, ‘Ascend, ascend! large palaces are ready for you, large couches are ready for you and your pupils’."