If you have heard objections like these or even thought them your self, you will be well-served by considering this capable scholar’s answer. Carson wrote:
Christians, of course, cannot forget that during his lifetime Jesus himself trained people to go and herald the good news. Christians remember that Jesus was sent by his Father, he insisted, to seek and save those who are lost. So it is not too surprising that he in turn sends his followers. That's what our word "mission" means: it derives from the verb "to send." "As the Father has sent me," Jesus once said, "I am sending you" (John 20:21 NIV). Among his last recorded words are these: "All authority in heaven and on earth has been given to me. Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age" (Matt 28:20 NIV). So Christians, understandably, will entertain a high view of those who actively seek to discharge Jesus' mission.
There are two common objections raised against this Christian view of missionary endeavor. It's worth reflecting on them before we contemplate the most convincing reason why missionary work is essential.
First, Jesus himself insists, "Do not judge, or you too will be judged" (Matt 7:1 NIV). Doesn't this mean that if we follow Jesus' teaching we should refuse to make moral and religious evaluations? Certainly that view is common on the street. "I don't mind Jesus," we hear; "it's Christians I can't stand. Christians run around self-righteously telling people how to live, condemning other religions, sending missionaries off to meddle in other cultures. Why don't they follow the instruction of the Jesus they claim to serve? After all, he said, 'Do not judge, or you too will be judged.'"
When I was a boy I learned a few of the first principles of interpreting texts. I learned, "A text without a context becomes a pretext for a proof-text." So I suppose we better remind ourselves of the context where Jesus says, "Do not judge, or you too will be judged." It's found in the Sermon on the Mount. That sermon contains quite a few teachings of Jesus. Here, for example, Jesus criticizes the man who looks at a woman lustfully, on the ground that such a man has already committed adultery in his heart (Matt 5:28). Here he teaches us not to store up treasures on earth, where moths and vermin destroy and where thieves break in and steal; rather, we must store up for ourselves treasures in heaven, knowing that where our treasure is, there our hearts will be, too (6:19-21). Here he tells us to watch out for false prophets, which presupposes we must make distinctions between the true and the false (7:15-20). Here he insists that on the last day not everyone who says to him "Lord, Lord" will enter the kingdom of heaven, but only the one who does the will of his Father who is in heaven (7:21-23). In all these utterances, Jesus is making moral, religious, and cultural evaluations. He is, in short, making judgments. So after making all these judgments, what does he mean by saying "Do not judge, or you too will be judged"? The context shows that he means something like "Do not be cheaply critical, or you will be subjected to the same criticism." In other words, there is no way on God's green earth that this command prohibits his followers from making moral judgements, when making moral judgements is precisely what the sweep of his teaching demands that they do. But he does insist that when they follow his instruction and make evaluations and judgments they must do so without cheap criticism of others-a notoriously difficult requirement. There must be no condescension, no double standard, no sense of superiority, no patronizing sentimentality. Christians are never more than poor beggars telling other poor beggars where there is bread. This humble tone ought to characterize all Christian witness, all Christian missionary endeavor. But to argue that Jesus wants his followers to make no judgments at all merely betrays biblical illiteracy.
Second, people often protest, "Yes, but isn't missionary work, indeed all attempts at trying to win another to your faith, terribly intolerant?" Well, no-not if one operates with older definitions of tolerance. Tolerance used to be understood to be the stance which, while disagreeing with another's views, guarded the right of those views to be heard. The new tolerance insists that disagreeing with another's views, saying they are wrong, is intrinsically intolerant. But frankly, that notion of intolerance is incoherent. The Labour Party doesn't agree with the Conservatives; Marxists don't agree with Capitalists; Muslims don't agree with Christians. Each pair may acknowledge some commonalities, but on many fronts, they differ. Yet each tolerates the other if each insists that the other has equal right to speak and convince others of their position. Intolerance is introduced, not when one says another party is wrong, but only when the views of others are quelled by force or corruption. If missionaries try to impose their views on others by force of any kind, they have lost the richest Christian heritage; where they seek to teach and put their case, all the while loving others sacrificially, they are upholding the highest standards of both intellectual integrity and tolerance.
But the best warrant for Christian mission is Jesus himself. He claims all authority is his, but he speaks not as a cosmic bully but as the crucified Lord. He insists that men and women have rebelled against his heavenly Father, but he joins himself to the human rebels so as to identify with them. He declares they deserve punishment, then bears the punishment himself. He claims to be the Judge they will meet on the last day, and meanwhile entreats them to turn to him, to trust him, and live. If one is going to follow a leader, what better leader than the one who demonstrates his love for his followers by dying on a cross to win them to himself? What political leader does that? What religious leader does that? Only God does that!
And then, in a small piece of mimicry, his followers are challenged to take up their cross and follow him. If one of the results is a worldwide missionary movement, I for one will pray for it to thrive.