And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.
Matthew 24:14

And straightway many were gathered together, insomuch that there was no room to receive [them], no, not so much as about the door: and he preached the word unto them.
Mark 2:2

And they went out, and preached that men should repent.
Mark 6:12

And He said to them, "Go into all the world and preach the gospel to every creature. He who believes and is baptized will be saved; but he who does not believe will be condemned.

And these signs will follow those who believe: In My name they will cast out demons; they will speak with new tongues; they will take up serpents; and if they drink anything deadly, it will by no means hurt them; they will lay hands on the sick, and they will recover."

So then, after the Lord had spoken to them, He was received up into heaven, and sat down at the right hand of God. And they went out and preached everywhere, the Lord working with [them] and confirming the word through the accompanying signs. Amen.
Mark 16:15-20

John used many such warnings as he announced the Good News to the people.
Luke 3:18 (NLT)

Then Jesus answering said unto them, Go your way, and tell John what things ye have seen and heard; how that the blind see, the lame walk, the lepers are cleansed, the deaf hear, the dead are raised, to the poor the gospel is preached.
Luke 7:22

"Until John the Baptist began to preach, the laws of Moses and the messages of the prophets were your guides. But now the Good News of the Kingdom of God is preached, and eager multitudes are forcing their way in.
Luke 16:16 (NLT)

And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.
Luke 24:47

And they, when they had testified and preached the word of the Lord, returned to Jerusalem, and preached the gospel in many villages of the Samaritans. . . Then Philip opened his mouth, and began at the same scripture, and preached unto him Jesus. . . But Philip was found at Azotus: and passing through he preached in all the cities, till he came to Caesarea.
Acts 8:25, 35, 40

But before he came, John the Baptist preached the need for everyone in Israel to turn from sin and turn to God and be baptized.
Acts 13:24 (NLT)

And there they preached the gospel. . . And when they had preached the gospel to that city, and had taught many, they returned again to Lystra, and [to] Iconium, and Antioch, . . . And when they had preached the word in Perga, they went down into Attalia . . .
Acts 14:7, 21, 25

And some days after Paul said unto Barnabas, Let us go again and visit our brethren in every city where we have preached the word of the Lord, [and see] how they do.
Acts 15:36

Did I commit sin in humbling myself that you might be exalted, because I preached the gospel of God to you free of charge?
2 Corinthians 11:7

And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand, [saying], "In you all the nations shall be blessed."
Galatians 3:8

He came and preached peace to you who were far away and peace to those who were near.
Ephesians 2:17 (NIV)

And you, who once were alienated and enemies in your mind by wicked works, yet now He has reconciled in the body of His flesh through death, to present you holy, and blameless, and above reproach in His sight-- if indeed you continue in the faith, grounded and steadfast, and are not moved away from the hope of the gospel which you heard, which was preached to every creature under heaven, of which I, Paul, became a minister.
Colossians 1:21-23

By which also he went and preached unto the spirits in prison. . .
1 Peter 3:19