I think the facts and sources in Barnabas' bio explain it well. The book of St. Matthew's parish transcriptions shows Barnabas married Jone Fletcher on June 23rd, 1636. (You can see an image of the relevant book page here: https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS9Y-K7DN-M )
Mary, daughter of Barnabas was baptised September 25th 1636. (Image here: https://www.familysearch.org/ark:/61903/3:1:3Q9M-CS9Y-K7Z2-T )
Barnabas married Mary Langton around 1639.