The Hebrew words ‘Isaac was forty years old’ in Genesis 25:20 numerically add up to 969 and the number ‘969’ is the fulfilment number for the church and represents the Rapture.
As such, this mathematical narrative supports the Rapture of the church at the conclusion of 40 Jubilees (which represent the 2000 bible years of the Christian Dispensation).
It is important to note that Isaac, who was a strong type of Messiah, was 40 years old when he took Rebekah as wife, just as Messiah at 40 Jubilees (of His life in the flesh) will take His wife (the church or Bride of Christ) at the Rapture.