The word For connects verse 4 both to verse 3, indicating why Paul is concerned, and to verse 1, indicating why he expects that they should bear with him also, since they are willing to tolerate those who preach a gospel contrary to what Paul preaches. New American Bible shows the connection more clearly by beginning this verse “I say this because….”

The words if some one comes should not be understood to mean that Paul is talking about a hypothetical situation, that is, about an event only imagined, but one which could indeed happen at any time. Verses 19-20 make clear that he is dealing with a problem already present in Corinth. To avoid suggesting that Paul is speaking hypothetically, Good News Translation omits the word if. And other English versions use “when” or “whenever.” The words some one may refer to a group or possibly to a representative person. Though the relationship with verse 5 is not entirely clear, Paul is probably referring to a representative from the group he calls the “superlative apostles” in the next verse (see also 12.11). Paul appears to be referring to someone from outside the Corinthian church, so Revised English Bible says “if some newcomer proclaims.” Or, to avoid giving the impression that Paul is not referring to a real life situation, one may prefer to say “whenever a newcomer comes and….”

Preaches another Jesus: in many languages it is awkward to talk about “preaching a person.” Rather it is more natural to say “preach a message about a person” or “preach the story of a person.” Although expressions like “preach Jesus” may have entered into the vocabulary of church members, translators should avoid language that is exclusive to Christians and use what is most natural for all speakers of the language. The idea is clearly that of preaching a message that is not consistent with the facts about Jesus. Some may say “tells you about a different Jesus” or “preaches another message concerning Jesus.”

Implicit in the expressions from the one you received and from the one you accepted is that the Corinthians received a spirit and accepted a gospel “from us,” that is, from Paul and his associates. Good News Translation and Bible en français courant make this information explicit.

You submit to it readily enough: this part of the verse may have to be transposed to a position much earlier in the structure of some languages, as in Good News Translation “you gladly tolerate….” It may also be necessary to break the verse down into two or more sentences:
• You seem so eager to accept a new person when he comes and tells you about a different Jesus. That is not the Jesus we told you about. And you happily pay attention when you receive a spirit and a message that are not like the Spirit and the message that we brought to you.

A different sort of restructuring of this verse is found in Contemporary English Version:
• We told you about Jesus, and you received the Holy Spirit and accepted our message. But you let some people tell you about another Jesus. Now you are ready to receive another spirit and accept another message.

Quoted with permission from Omanson, Roger L. and Ellingworth, Paul. A Handbook on Paul’s Second Letter to the Corinthians. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .