The ekklesia are those "called-out" before the
foundation of the world (Eph 1:4) who are being built by Jesus
upon the rock (the revelation that Jesus is the Messiah,
who will rule the earth (Matt 16:13-20). "Flesh and blood" cannot
reveal this to mankind; it must come from God the Father.
The ekklesia are being "built up as a spiritual house"
(1 Peter 2:4-5) to "rule upon the earth" (Rev 5:9-10).
"Many are called" but few choose to "take up their cross and
follow Jesus in His discipline (Heb 12:4-6) to be made
disciples ("learners of Christ"; Matt 11:29).
The discipleship training period is life here on earth!
Therefore, "be diligent to present yourself approved to God as a
workman who does not need to be ashamed, accurately handling the
word of truth." (1 Timothy 2:15)