Why does Paul refer to himself as an “abortion” in 1 Cor. 15: 8?
In listing the witnesses of the resurrection Paul recounts that "last of all, as to an abortion, he appeared to me also" (v8). Instead of "abortion", the AV has "one born out of due time" and we are apt to infer from this that Paul was not only "last of all" but much later than the others in witnessing the resurrection. This is true, but it is not what he is saying here. The Greek word ektrwma (ektroma) has a more exact and enlightening translation of one born prematurely—one born before his time (compare Job 3: 16). This figure of premature birth that the Apostle applies to himself is full of meaning. To grasp its force we must first look elsewhere in the NT before we consider 1 Cor. 15.
Initially, it must appear odd that one who stated "I am apostle of nations" (Rom. 11: 13) should be the only NT writer to stress the distinctiveness of his Jewish pedigree several times (see Acts 22: 3; 2 Cor. 11: 22; Phil. 3: 5). 1 Cor. 15: 8 must be carefully weighed in the light of this fact.
Throughout the book of Acts the main opposition to Gentile blessing came from the Jewish nation, and the unconverted Paul was their most prominent antagonist. His conversion was not by hearing a preaching, for no human intermediary was involved. Instead he was converted directly by the Lord Himself appearing to him in glory. His conversion was sudden and immediate although his apostleship was marked out from his "mother’s womb" (Gal. 1: 15).
Looking now at the relevant verses in 1 Cor. 15, Paul says of the Lord that "he appeared to James; then to all the apostles; and last of all, as to an abortion, he appeared to me also. For I am the least of the apostles, who am not fit to be called apostle, because I have persecuted the assembly of God" (vs 7, 8, 9). It is in the context of the Lord’s appearing in resurrection and Paul’s conversion and apostleship that Paul speaks of himself of one born prematurely. Now what God did with Paul as an individual, He will yet do with Israel as a nation.
Let us see the parallel in Israel as a nation. Paul says "all Israel shall be saved". How? By preaching? No, but "According as it is written, The deliverer shall come out of Zion" (Rom. 11: 26). It is by the Messiah’s appearing in glory, when "they shall look on me whom they pierced" (Zech. 12: 10) that the nation will be converted. Isaiah’s question "shall a nation be born at once?" (Is. 66: 8) will get its answer in the immediacy of their conversion. The reality of that new birth will be seen in the immense sorrow of their repentance (see Zech. 12: 10–13: 9). However, as well as the parallel between Paul’s conversion and Israel’s future salvation, I think that there is even more in 1 Cor. 15: 8. He speaks of himself as an "abortion" not only in the context of his conversion but also his apostleship. Now Paul’s apostleship was to Gentiles, not Jews, for the Lord had said "I will send thee to the nations afar off" (Acts 22: 21; see also 26: 17). As such Paul is the forerunner of the Jewish emissaries to the nations in a coming day.
In Matt 28: 19 the Lord commanded his disciples to "Go [therefore] and make disciples of all the nations". Contrary to popular belief, there is no definite Scriptural record of this commission ever being carried out by them. Quite to the contrary, the mission to the Gentiles was given up to Paul (see Gal. 2: 7–10) who states explicitly that the Lord "has not sent me to baptise" (1 Cor. 1: 17). This submission of the nations by baptism to the authority of a Messiah on earth has yet to be fulfilled. While baptism in the Acts and the Epistles is always to the name of the Lord Jesus, in Matt. 28 it is to the triune Name of Father, Son and Holy Spirit. The discipling of all nations and teaching them when the Lord is here is quite a different thing from a testimony to all nations prior to the Lord’s coming as given in Matt. 24: 14. There is no preaching of any Gospel in Matt. 28, only discipleship and adherence to the ordinances of the Kingdom by baptism. On the Lord’s return to earth in a coming day the false religions of the nations and their gods will all have to submit to His authority. From the multiplicity of gods in Hinduism to the singularity of deity in Islam—all must yield to the triune Name. David’s exhortation in 1 Chron. 16: 24–29 will then be answered: "Declare his glory among the nations, His wondrous works among all peoples. For Jehovah is great, and exceedingly to be praised; And he is terrible above all gods. For all the gods of the peoples are idols … Give unto Jehovah, ye families of peoples, Give unto Jehovah glory and strength! Give unto Jehovah the glory of his name!".