The strongest case for charitable work to benefit non-Christians comes from the words of Jesus, but these are often not nearly as non-Christian oriented as we assume. For example, Jesus’ famous Judgment Day description in Matt 25 speaks to caring for the “least of these,” generally assumed to be a reference to the poor regardless of their faith. But the commentators uniformly reach a different conclusion.
(Matt. 25:34-40 ESV) 34 Then the King will say to those on his right, ‘Come, you who are blessed by my Father, inherit the kingdom prepared for you from the foundation of the world. 35 For I was hungry and you gave me food, I was thirsty and you gave me drink, I was a stranger and you welcomed me, 36 I was naked and you clothed me, I was sick and you visited me, I was in prison and you came to me.’ 37 Then the righteous will answer him, saying, ‘Lord, when did we see you hungry and feed you, or thirsty and give you drink? 38 And when did we see you a stranger and welcome you, or naked and clothe you? 39 And when did we see you sick or in prison and visit you?’ 40 And the King will answer them, ‘Truly, I say to you, as you did it to one of the least of these my brothers, you did it to me.’
Notice that Jesus refers to those who should have been helped in v. 40 as “my brothers.” Fellow sons of God. The NET Bible translator notes state,
… Jesus is ultimately speaking of his “followers” (whether men or women, adults or children), but the familial connotation of “brothers and sisters” is also important to retain here.
The case is even stronger than that —
In some Jewish apocalyptic texts, the nations would be judged for how they treated Israel. In the Bible, God also judged people for how they treated the poor. But given the use of “brothers” or “sisters” (12:50; 28:10; the Greek term can include both genders) and perhaps “least” (5:19; 11:11; cf. 18:4; 20:26; 23:11) elsewhere in Matthew, this passage probably refers to receiving messengers of Christ. Such missionaries needed shelter, food and help in imprisonment and other complications caused by persecution; see comment on 10:11-14. Receiving them was like receiving Christ (on the Jewish principle of agency, see comment on 10:40-42). The judgment of all nations thus had to be preceded by the proclamation of the kingdom among them (24:14).
Craig S. Keener, The IVP Bible Background Commentary: New Testament, Accordance electronic ed. (Downers Grove: InterVarsity Press, 1993), 118.
For Jesus’ brethren, cf. 12:48–50; 28:10. It is a term specially for his disciples, not for men in general. The reference to the least of these in this connection reminds us of ‘these little ones’ in 10:42, which was taken up more fully in 18:6, 10, 14. (See above, on these verses and on 18:5.) In 10:42 the reference is particularly to disciples sent out in the master’s name; in ch. 18 it refers more to relationships within the church. It seems, therefore, inappropriate to relate ‘the least of these’ here to a specific group. It is in any brother of Jesus, however insignificant, that Jesus himself is served, and it is that service which is therefore the criterion of judgment, as it indicates how one responds to Jesus himself. It is important to note that, in each of the passages which refer to ‘these little ones’, the point is to declare the importance of such people because of their identification with Jesus (see esp. 10:40, 42; 18:5). ‘It is the nearest that Matthew, or the synoptic tradition generally, comes to the conception of the Church as the Body of Christ’ (Green, p. 206).
R. T. France, Matthew: An Introduction and Commentary, Tyndale NTC 1; IVP/Accordance electronic ed. (Downers Grove: InterVarsity Press, 1985), 360-361.
In short, Jesus is saying that we’ll be judged by how we treat his followers, not how we treat the poor in general. This is really shocking, but the text is clear, and the commentators are united in their reading. The commentators remind us that Jesus has a heart for those who are not his followers as well, but that is not what this passages is addressing.
The Sermon on the Mount does deal very specifically with unbelievers. For example,
(Matt. 5:38-42 ESV) 38 “You have heard that it was said, ‘An eye for an eye and a tooth for a tooth.’ 39 But I say to you, Do not resist the one who is evil. But if anyone slaps you on the right cheek, turn to him the other also. 40 And if anyone would sue you and take your tunic, let him have your cloak as well. 41 And if anyone forces you to go one mile, go with him two miles. 42 Give to the one who begs from you, and do not refuse the one who would borrow from you.”
This passage includes several allusions to commands found in Torah that speak to how Jews are to treat other Jews. “An eye for an eye” is part of the Torah’s civil code for how criminals are to be punished — the punishment should fit the crime. Lawsuits were only possible among fellow Jews. Non-citizens would not have been subject to the jurisdiction of Jewish courts. The command to lend to the poor is found in Torah and relates only to fellow Jews and to sojourners.
However, the command to go the extra mile seems to be based on the Roman law allowing a Roman soldier to require anyone to carry his pack for a mile. Jesus plainly teaches that the Jews should treat their Roman occupiers better than Roman law requires.
Just so, turning the other cheek would seem to apply to anyone who might insult you, which in Jesus’ day was hardly limited to fellow Jews. Plainly, Jesus is teaching that our ethics with regard to those outside the church have to rise above the minimum requirements of civil law. We must treat unbelievers better than the law requires for the sake of Jesus.
He gives the reason in the following verses —
(Matt. 5:43-48 ESV) 43 “You have heard that it was said, ‘You shall love your neighbor and hate your enemy.’ 44 But I say to you, Love your enemies and pray for those who persecute you, 45 so that you may be sons of your Father who is in heaven. For he makes his sun rise on the evil and on the good, and sends rain on the just and on the unjust. 46 For if you love those who love you, what reward do you have? Do not even the tax collectors do the same? 47 And if you greet only your brothers, what more are you doing than others? Do not even the Gentiles do the same? 48 You therefore must be perfect, as your heavenly Father is perfect.”
“Love your enemies” obviously takes Christian ethics outside the Christian community. Our enemies are necessarily unbelievers — and we’re required to love them and act on that basis. Why?
So that we’ll be perfect as God is perfect — the God who “makes his sun rise on the evil and on the good, and sends rain on the just and the unjust.” We are to do good works for both believers and unbelievers. Jesus is quite plain.
Therefore, Jesus teaches us to love one another, and he expects the church — the community of believers — to live in a mutual, sacrificial love, a love so intense that the lost are drawn toward Jesus because of how we treat each other. But we are to love unbelievers, too. The love may not be reciprocated and it cannot form communities that are like the church. Nonetheless, we must love those outside the church — and if we love unbelievers, we’ll do good things for them as we have opportunity.
What we won’t do is try to make the lost world act like the Kingdom. We’ll love the lost, tell the lost about Jesus, and do good for the lost in the name of Jesus. But our goal is not to make the world act like the church; it’s to draw people out of the world into the church.