What can we learn from the date of Jesus Birth

Sermon synopsis: Exodus 12:1 The Lord said to Moses and Aaron in Egypt, (2)This month is to be for you the first month, the first month of your year.

Luke 2:8 And there were shepherds living out in the fields nearby, keeping watch over their flocks at night.

The date of Jesus' birth; is it important? But more importantly, what can we learn from it? This sermon will put forward a theory; just for a bit of fun - it will give the date later in the sermon.