Sinodos 4:14, "Keep also the feast of Pentecost, fifty days after the Resurrection, in remembrance of the descent of the Holy Spirit upon the apostles." This verse can be found on page 1824 of the PDF file at Ethiopian-Bible-1.pdf

There are 88 books in the Ethiopian Bible while the King James has only 66 books. The Ethiopian Bible also contains the book of 1 Enoch which begins on page 716 of the above PDF file.  The reason why I posted Sinodos 4:14 is the fact that some people believe that Pentecost took place the 100th day after the Resurrection instead of 50 days.