Jamieson, Fausset and Brown on 1 Peter 1:8

8. not having seen, ye love--though in other cases it is knowledge of the person that produces love to him. They are more "blessed that have not seen and yet have believed," than they who believed because they have seen. On Peter's own love to Jesus, compare Joh 21:15-17. Though the apostles had seen Him, they now ceased to know Him merely after the flesh.

in whom--connected with "believing": the result of which is "ye rejoice" (Greek, "exult").

now--in the present state, as contrasted with the future state when believers "shall see His face."

unspeakable--(1Co 2:9).

full of glory--Greek, "glorified." A joy now already encompassed with glory. The "glory" is partly in present possession, through the presence of Christ, "the Lord of glory," in the soul; partly in assured anticipation. "The Christian's joy is bound up with love to Jesus: its ground is faith; it is not therefore either self-seeking or self-sufficient" [Steiger].