“And no man takes this honor to himself, but he who is called by God, just as Aaron was.” Hebrews 5:4 (NKJV)
Aaron was called to the priesthood in Israel, and now, Jesus has opened “a new and living way, which he has consecrated for us,” Hebrews 10:20. God is calling out a special group, the Church, to be “a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light,” 1 Peter 2:9.
We are called when the Lord shows us the glorious opportunity of consecrating our lives to His service. It is a heavenly calling (Hebrews 3:1) because if faithful, we will share in His resurrection. Ephesians 1:18, Hebrews 3:1 (NKJV), “The eyes of your understanding being enlightened; that you may know what is the hope of His calling, what are the riches of the glory of His inheritance in the saints.”
The Lord’s call is “Gather my saints together unto me, those who have made a covenant with me by sacrifice.” (Psalm 50:5). Sacrifice is an essential aspect of this call. Jesus said, “Whoever desires to come after Me, let him deny himself, and take up his cross, and follow Me,” Mark 8:34.
Those who accept the call are adopted as children of God. The faithful children, who are led by the spirit, become fellow heirs with Christ. Romans 8:14-17, “For all who are led by the Spirit of God are sons of God….The Spirit itself bears witness with our spirit that we are children of God, and if children, then heirs–heirs of God and fellow heirs with Christ, provided we suffer with him in order that we may also be glorified with him.”
When glorified with Him, the Christ (head and body) will bless all the families of the earth.
Summary: The called are those who have a hearing ear and a ready heart and enter into a covenant of sacrifice with God. They become His Church.