. . . this day have I begotten thee. Ask of me and I will give thee the gentiles for they inheritance and for they possessions the ends of the earth. (And to show that) he has raised him up from the dead in such a way as never again to return to decay, that all the people may know and do penance (he has said thus) this namely is the way which is written in Isaias the prophet, I will give you the holy and everlasting covenant and sure (promises) mercies of David. (Theodore C. Petersen, "An Early Coptic Manuscript of Acts: An Unrevised Version of the Ancient So-called Western Text," CBQ 26/2 [1964], 240)
The italicized phrases represent the Coptic additions over the critical Greek text. But I'm especially interested in the italicized and bold phrase, "everlasting covenant." Any help?