#Yalkut (13th century), Section 621 On verse 7: R. Huna said in the name of R. Idi, In three parts were the punishments divided: one for King Messiah, and when His hour cometh the Holy One, blessed be He, saith, I must make a new covenant with Him, and so He saith, To-day have I begotten thee.
The Baraita of the Forty-nine Rules (Hebrew: ברייתא מ"ט מדות) is a work of rabbinical literature which is no longer in existence except in references by later authorities. Rashi, the Tosafists, Abraham ibn Ezra, Yalḳut, and Asher ben Jehiel mention a work, "Baraita of the Forty-nine Rules," and make citations from it (thus, Rashi, ed. Berliner, on Ex. xxvi. 5; Yalḳ., Gen. 61, calls it "Midrash"; Rashi on Ex. xxvii. 6 calls it "Mishnah").
The first part, the midrash proper, is found also in the Yalḳuṭ to Jonah (part ii., §§ 550-551), with the exception of a few missing passages and with several variations; but here the Pirḳe Rabbi Eli'ezer is given as the source (for some passages, Yerushalmi and Babli).
In 1971, when he was 18 and studying at Yeshivat HaNegev, he collected halakhic rulings from the five volumes of Yavia Omer, the book of his father's responsa, that had been published by then, and published them in the book Yalkut Yosef.