Jesus didn't have a crafted mission statement that he repeated verbatim. However, he did on many occasions give statements of purpose most of which all say pretty much the same thing in different ways.
John 6:38 "For I have come down from heaven, not to do My own will, but the will of Him who sent Me.
What is God's will? His will is "not wishing for any to perish but for all to come to repentance" (2 Pet 3:9b). This is why Jesus said,
"For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life. For God did not send the Son into the world to judge the world, but that the world might be saved through Him" (John 3:16-17).
Jesus said his ministry was fulfillment of the scripture that says, "THE SPIRIT OF THE LORD IS UPON ME, BECAUSE HE ANOINTED ME TO PREACH THE GOSPEL TO THE POOR. HE HAS SENT ME TO PROCLAIM RELEASE TO THE CAPTIVES, AND RECOVERY OF SIGHT TO THE BLIND, TO SET FREE THOSE WHO ARE OPPRESSED, TO PROCLAIM THE FAVORABLE YEAR OF THE LORD" (Lk 4:18-19).
The good news of redemption and reconciliation came through the death of Jesus for our sins and his resurrection. As he approached the hour of his crucifixion, he resolutely stepped forward, he said, "for this purpose I came to this hour" (Jn 12:27).
Jesus clearly understood his purpose and faithfully fulfilled it. But his mission did not end when he ascended to the Father. His plan was still in motion. He said, " "Thus it is written, that the Christ would suffer and rise again from the dead the third day, and that repentance for forgiveness of sins would be proclaimed in His name to all the nations, beginning from Jerusalem" (Lk 24:46-47)."
There was still more to do. He passed on the baton to his followers. With all the authority of God, He charged them to "Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit, teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age" (Mt 28:19-20).
This means that his mission to "seek and save the lost" (Lk 19:10), has been passed on to us, the church. This is why he calls us the light of the world (Mt 5:14-16). This is why we have the examples in Acts of the church going about everywhere preaching the word (Acts 8:4).
The mission is pretty clear. The church is not only to keep the faith, but also to share the faith. There needs to be a balance between the two. To do one to the exclusion of the other is unbalanced, truncated, and incomplete. To be faithful to God's purposes, we do both. All of our ministries need to keep this dual purpose in mind. They may not fulfill them in the same manner, but they fulfill them nonetheless. It is good to ask the dual question - "How does this keep the faith? and, "How does this share the faith?"