In the Greek God is my witness that I tell you the truth is simply “God is my witness.” This expression is used by Paul to convey solemn intense, personal emotion (cf. Rom 1.9; 2 Cor 1.23; 1 Thes 2.5, 10). He appeals to God as the One who knows and who can testify to the truthfulness of his innermost feelings. It may be expressed in some instances as “God knows that what I say is true,” or “… this that I am going to say is true.”

Comes from the heart of Christ Jesus himself translates a Greek prepositional phrase, literally “with the entrails of Christ.” The entrails consist of the heart, liver, and lungs. In biblical times these were collectively regarded as the seat of feelings and affections, the equivalent of “heart” in modern usage. Paul identifies himself so closely with Christ that the deep feeling he has towards his Christian friends appears to be nothing other than the love of Christ himself (Jerusalem Bible “loving you as Christ Jesus loves you”).

The final clause of verse 8 may be very difficult to render, for it contains two metaphorical expressions, deep feeling and heart. Furthermore, it is impossible to say in some languages that “a feeling comes.” The meaning here is, of course, that the true source of Paul’s feelings is Christ. But the emphasis is upon the similarity of his affections to Christ’s, and therefore this clause may be rendered as “I love you in the same way that Christ Jesus himself loves you.” Or it may be possible to render this clause as “my love for you all results from the kind of love which Christ Jesus himself has shown.”

Quoted with permission from Luo, I-Jin. and Nida, Eugene A. A Handbook on Paul’s Letter to the Philippians. (UBS Handbook Series). New York: UBS, 1977. For this and other handbooks for translators see here .