Leviticus 23:15

Ye shall count unto you - seven Sabbaths - That is, from the sixteenth of the first month to the sixth of the third month. These seven weeks, called here Sabbaths, were to be complete, i. e., the forty-nine days must be finished, and the next day, the fiftieth, is what, from the Septuagint, we call pentecost. See the note on Luke 6:1 .