Jesus preached:
Luk 4:43 but he said to them, “I must preach the good news of the kingdom of God to the other towns as well; for I was sent for this purpose.”
 
The apostles preached:
Mar 3:14 And he appointed twelve (whom he also named apostles) so that they might be with him and he might send them out to preach
 
Jesus commanded them to preach:
Act 10:42 And he commanded us to preach to the people and to testify that he is the one appointed by God to be judge of the living and the dead.
 
Preaching is how people are saved:
1Co 1:21 For since, in the wisdom of God, the world did not know God through wisdom, it pleased God through the folly of what we preach to save those who believe.
 
Woe to those who don’t:
1Co 9:16 For if I preach the gospel, that gives me no ground for boasting. For necessity is laid upon me. Woe to me if I do not preach the gospel!
 
The charge!
2Ti 4:1-4 I charge you in the presence of God and of Christ Jesus, who is to judge the living and the dead, and by his appearing and his kingdom: preach the word; be ready in season and out of season; reprove, rebuke, and exhort, with complete patience and teaching. For the time is coming when people will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions, and will turn away from listening to the truth and wander off into myths.
 
Rom 10:15 And how are they to preach unless they are sent? As it is written, “How beautiful are the feet of those who preach the good news!”
 
Tolerance avoids confrontation in order to maintain ‘peace.’ Love tells the truth boldly and graciously in order to bring about a deeper, more lasting peace.”
-Trevin Wax from Holy Subversion (pp 146)