1Cor 15:6 | RWP | e4.org | To above five hundred brethren at once ( επανω πεντακοσιοις αδελφοις εφαπαξ ). Επανω here is just an adverb with no effect on the case. As a preposition with the ablative see . This incident is the one described in the prearranged meeting on the mountain in Galilee. The strength of this witness lies in the fact that the majority ( ο πλειους ) of them were still living when Paul wrote this Epistle, say spring of A.D. 54 or 55, not over 25 years after Christ's resurrection.

‏ 1 Corinthians 15:6

To above five hundred brethren at once ( επανω πεντακοσιοις αδελφοις εφαπαξ ). Επανω here is just an adverb with no effect on the case. As a preposition with the ablative see Mt 5:14. This incident is the one described in Mt 28:16 the prearranged meeting on the mountain in Galilee. The strength of this witness lies in the fact that the majority ( ο πλειους ) of them were still living when Paul wrote this Epistle, say spring of A.D. 54 or 55, not over 25 years after Christ's resurrection.