The Hebrew writer tells us that in our Christian endeavor we are partakers of a heavenly calling.
Heb. 3:1“Therefore, holy brethren, partakers of a heavenly calling, consider Jesus…”
It is a call both from heaven, and to heaven, but it is given on earth that God has told us to repeat over and over and over making sure that anyone who wants to come will have a chance to hear the calling.
Rev. 22:17“And the Spirit and the bride say, “Come.” And let the one who hears say, “Come.” And let the one who is thirsty come; let the one who wishes take the water of life without cost.”
This is exactly what Jesus did with the apostles. He was sent, and He sends others to spread the His message.
Jn. 20:21“Jesus therefore said to them again, “Peace be with you; as the Father has sent Me, I also send you.”
So with the heavenly calling. The origin is heaven, but the call is spread by those who have already accept it. The supernatural portion was the origin; the effectiveness is based in God’s will; providential care and blessings protect and promote the call and we repeat God’s call to all who will hear.