{And that he may send the Christ who hath been appointed for
you, even Jesus} (kai aposteil(8869) ton prokecheirismenon humin
Christon I(8873)oun). First aorist active subjunctive with hop(9373)
an as in  15:17  and  Lu 2:35 . There is little real difference
in idea between hop(9373) an and hina an. There is a conditional
element in all purpose clauses. The reference is naturally to the
second coming of Christ as verse  21  shows. Knowling admits
"that there is a spiritual presence of the enthroned Jesus which
believers enjoy as a foretaste of the visible and glorious
Presence of the Parousia." Jesus did promise to be with the
disciples all the days ( Mt 28:20 ), and certainly repentance
with accompanying seasons of refreshing help get the world ready
for the coming of the King. The word prokecheirismenon (perfect
passive participle of procheiriz(935c), from procheiros, at hand,
to take into one's hands, to choose) is the correct text here,
not prokek(8872)ugmenon. In the N.T. only here and  Ac 22:14  26:16 . It is not "Jesus Christ" here nor "Christ Jesus," but
"the Messiah, Jesus," identifying Jesus with the Messiah. See the
Second Epiphany of Jesus foretold also in  1Ti 6:15  and the
First Epiphany described in  1Pe 1:20 .