This is the second in an Advent series by Dr Andrew Ollerton.

One of my favourite comedians, the Northerner Peter Kay, describes what happens when families come together for Christmas. All sorts of eccentric traditions surface and then there's a mad scramble to find enough 'emergency chairs' for Christmas dinner. How many of us have eaten our turkey roast down on a piano stool or up on a bar stool towering over the Brussels sprouts? Half the fun of Christmas is what happens when the whole family comes together.

Today we consider Christmas according to Matthew's gospel, which brings the whole Bible family together. Matthew deliberately introduces the famous stories of innkeepers and wise men with a long genealogy – Jesus' family tree. These long lists of names can feel hard work – like reading the Hebrew telephone directory. But think of genealogies as a shorthand way of summoning up the whole story of the family of God. In other words, Matthew frames the small stories of Christmas in the light of the big picture of the Bible.

So let's consider a few family members. First up Matthew highlights two male characters crucial to the Messiah. Jesus is 'son of David, son of Abraham' (1:1). By identifying Jesus with Abraham, Matthew links Christmas back to the beginning of Israel's story. After the goodness of creation turned ugly through sin, God called a Middle Eastern man, Abraham, to leave his family and start a new one – God's family. And God promised to so bless Abraham's family that 'all families on earth would be blessed'. Just as the fall of Adam brought curses to this world, the call of Abraham would bring back blessings. So when Matthew identifies the baby born in Bethlehem as 'Son of Abraham' it's his way of saying: 'Ta dah! World meet your long-awaited hope!' Or as the angel of the Lord put it: 'I bring you good news of great joy for all people' Or as the Christmas carol puts it: 'Joy to the world the Lord has come!'

Now fast-forward 800 years from Abraham and we meet the other important male character in Jesus' family tree – king David. Why David? Well he exemplified Israel's victorious king – slaying the mighty Goliath and bringing peace. Towards the end of his life, God promised David a future ancestor who would be the king to end all kings. The ultimate ruler not just of Israel but the world. That's why Matthew identifies Jesus as 'son of David'. It's his way of saying: 'Here he is! Israel meet your king who will rule the world!'

Listen to how the angel put it to the teenage virgin Mary: 'the Lord will give to him the throne of his father David, and he will reign forever!' No wonder Matthew records prestigious Magi from roughly modern day Iran coming to worship Jesus with gold, Frankincense and Myrrh. The nations of the earth are welcoming the king of kings. Oh and by the way, guess where King David was born? Bethlehem. Does that ring any bells? As Joseph and Mary rock up in that little town they are fulfilling ancient prophecies all the way. As the prophet Micah declared hundreds of years before:

'You O Bethlehem in the land of Judah... from you shall come a ruler who will shepherd my people Israel' (Matthew 2:6)

Now back to Peter Kay and those emergency chairs. Matthew has highlighted the birth of Jesus as the fulfilment of an ancient plan stretching back via king David to father Abraham. But the Messiah's family is not quite as simple and respectable as that. Matthew also highlights four women who are part of Jesus' family history – Tamar the Canaanite who disguised herself as a roadside prostitute and slept with her father-in-law Judah (you know Judah, as in the Messiah's tribe); then there's Rahab the foreign prostitute from Jericho who escaped to Israel; Ruth the foreigner who staggered destitute into Bethlehem (there's that town again); and Bathsheba with whom the great king David had a scandalous affair. And this is the Messiah's family history – ouch!

But notice Matthew doesn't airbrush out these awkward realities – quite the opposite. Foreign females with chequered stories find an honoured place at the Messiah's table. Jesus didn't come from a nice, sorted, Ned Flanders family (for any Simpsons fans). His family history is more like ours - complicated, messy, painful - and yet deeply loved by God. Matthew's Christmas message is important: God's family is not limited to the good guys. He will pull out 'emergency chairs' and make a place at the table for people like you and me.

So on a practical note: this Christmas, let's not hide away from the messiness of family – whether our natural family or our church family. Yes it can be complicated but so was Jesus' family tree. Let's embrace the challenge, pray for peace and work for reconciliation. Perhaps there's someone you are at odds with where the relationship has broken down. Why not echo the Christmas story by deliberately seeking them out in love. Wouldn't it be great if, as a result, we had to dig out more 'emergency chairs' for Christmas dinner?

Dr Andrew Ollerton is author of The Bible Course and works with Bible Society. Follow him on Twitter @andyollerton