UNKNOWN GOD (Gr. agnōstos theos). These words occur only in Acts.17.23. When Paul came into Athens on his second missionary journey, he found the city “full of idols.” While disputing with the Jews in their synagogues and marketplaces, he was asked by the philosophers concerning his faith. On Mars Hill Paul began his message by saying, “I even found an altar with this inscription: To An Unknown God ” (Acts.17.23). This was probably a votive altar erected by some worshiper who did not know what god to thank for some benefit he had received. Using this as a starting point, Paul preached the true God to them. Altars erected to unknown gods were common in Athens.
). The inscr. observed by Paul on an altar at Athens, to which he referred in his Areopagus address (Acts 17:22-31
The existence of such an altar, presumably built in a scrupulous attempt to include every possible deity, was an indication of the Athenians’ religious sensitivity. It also betrayed a lack of religious knowledge, which Paul sought to remedy in his address.
As no comparable dedication to a single unknown deity has been found, the genuineness of this inscr. has been questioned. However, there is evidence of inscrs. to unknown deities in the pl. (Pausanius, Description of Greece i. 1. 4; Philostratus, Appolonius of Tyana vi. 3. 5; Diogenes Laertius, Lives of the Philosophers i. 110). It is also theorized that in a polytheistic culture, a single deity would not have been addressed, and that Paul might have altered a polytheistic inscr. to fit his monotheistic concepts. On the contrary, the syncretism of the Hel. period, the occasional merging of Jewish ideas with pagan forms, and the tendency toward both the unifying of principles and the personifying of abstract religious concepts, provided a matrix within which such an inscr. was not at all unlikely.
E. Norden, Agnostos Theos (1913); K. Lake, “The Unknown God,” in F. J. Foakes-Jackson and E. Lake, eds., The Beginnings of Christianity, Pt. 1, V (1933), 240-246; B. Gärtner, The Areopagus Speech and Natural Revelation (tr. C. H. King, 1955), 242-247.
International Standard Bible Encyclopedia (1915)
un-non’, (agnostos theos): In Ac 17:23 (St. Paul’s speech in Athens) the American Standard Revised Version reads: "I found also an altar with this inscription, To AN UNKNOWN GOD. What therefore ye worship in ignorance, this I set forth unto you." the King James Version and the English Revised Version margin translate "to the Unknown God," owing to the fact that in Greek certain words, of which theos is one, may drop the article when it is to be understood. In the present case the use of the article. is probably right (compare Ac 17:24). In addition, the King James Version reads "whom" and "him" in place of "what" and "this." The difference here is due to a variation in the Greek manuscripts, most of which support the King James Version. But internal probability is against the King James Version’s reading, as it would have been very easy for a scribe to change neuters (referring to the divine power) into masculines after "God," but not vice versa. Hence, modern editors (except yon Soden’s margin) have adopted the reading in the Revised Version (British and American).
Paul in Athens, "as he beheld the city full of idols," felt that God was truly unknown there. Hence the altar with the inscription struck him as particularly significant. Some Athenians, at any rate, felt the religious inadequacy of all known deities and were appealing to the God who they felt must exist, although they knew nothing definite about Him. No better starting-point for an address could be wished. What the inscription actually meant, however, is another question. Nothing is known about it. Altars dedicated "to unknown gods" (in the plural) seem to have been fairly common (Jerome on Tit 1:12; Pausanias, i.1,4; Philaster, Vita Apoll., vi.3), and Blase (Commentary ad loc.) has even suggested that the words in Ac were originally in the plural. But this would spoil the whole point of the speech, and the absence of references to a single inscription among thousands that existed can cause no surprise. Those inscriptions in the plural seem to have been meant in the sense "to the other deities that may exist in addition to those already known," but an inscription in the sing. could not have this meaning. Perhaps a votive inscription is meant, where the worshipper did not know which god to thank for some benefit received. That a slur on all the other Athenian objects of worship was intended is, however, most improbable, but Paul could not of course be expected to know the technical meaning of such inscriptions.