An apostle (“one sent on a mission”) is one whom God has sent on an errand or with a message. An apostle is accountable to his Sender and carries the authority of his Sender. An apostleship is the office an apostle holds.
Jesus Christ Himself has an “apostleship.” He wears “Apostle” as one of His descriptive titles (Hebrews 3:1). He was sent to earth by the Heavenly Father with God’s authoritative message, which He faithfully delivered (John 17:1–5).