Hitherto (heōs arti). Up till now the disciples had not used Christ’s name in prayer to the Father, but after the resurrection of Jesus they are to do so, a distinct plea for parity with the Father and for worship like the Father.
May be fulfilled (ēi peplērōmenē). Periphrastic perfect passive subjunctive of plēroō in a purpose clause with hina. See Joh 15:11 for some verb (first aorist passive subjunctive with hina) and 1Jo 1:4 for same form as here, emphasizing the abiding permanence of the joy.