"As understood here ("O Lord, come!"), it is a prayer for the early return of Christ. If the Aramaic words are divided differently (Maran atha, "Our Lord has come"), it becomes a credal declaration. The former interpretation is supported by what appears to be a Greek equivalent of this acclamation in Rev 22:20 "Amen. Come, Lord Jesus!""
The phrase seems to have been used as a greeting between Early Christians, and it is probably in this way that it was used by the Apostle Paul. However, the preceding word is the curse "anathema", and because the original texts of the Greek New Testament contained no punctuation at all, or indeed any word or sentence separation, early readers took the two words together and construed the passage as, "If any man love not the Lord Jesus Christ, let him be Anathema Maranatha". It was therefore believed that "anathema maranatha" must be some exceptionally severe kind of curse. The phrase was in use in this sense at least by the 7th Century, when Pope Silverius pronounced anyone who deceives a bishop as "anathema maranatha" (see the Catholic Encyclopedia article referenced below). One possible understanding of this is that the offender would be excluded from communion with the Church until the return of Christ, tying the punishment to the term Maranatha. John Wesley in his Notes on the Bible comments that, "It seems to have been customary with the Jews of that age, when they had pronounced any man an Anathema, to add the Syriac expression, Maran - atha, that is, "The Lord cometh;" namely, to execute vengeance upon him." The negative understanding of maranatha began to die out by the late 19th Century; Jamiesen, Fausset and Brown's commentary of 1871 separates Maranatha from anathema in the same way as modern scholars. However the traditional interpretation is still occasionally found among some of the more extreme conservative Christians to-day (e.g. ).
It is worth noting that, perhaps as a consequence of this interpretation, it has been maintained by some scholars that "Maranatha" is a mis-translation of the Hebrew phrase "mohoram atta", which means "you are put under the ban". If the original usage is understood as a greeting, however, this interpretation seems gratuitous.