Our experience of time is that it is linear. We have today; before that was yesterday – Saturday; before that, Friday and so on… ad infinitum – it would appear. It feels unnatural, according to our experience, to think there was a beginning to time. 
The Bible, of course, talks of a beginning. This is not the beginning of a story, but a point before which there was nothing – not just ‘no thing’, but nothing;    
     not just a void, the absence of matter - but a formless void, the absence of space as well
     darkness – not just absence the visible range of the electro-magnetic spectrum, but of all energy
     God’s act of creation was the beginning of everything associated with the universe; space, matter, light and even time itself. 
With the rise of science, this idea was rejected. Observation and logic suggested that time was infinite, space and matter permanent – and the Bible therefore wrong. However, as you will know, since the late 1930’s scientific opinion has swung behind the ‘Big Bang’ theory, which describes a single point at which time, space, energy and matter all came into existence – sometimes called a ‘singularity’. 
More and more there seems to be a coming together of science and the Biblical account. I love the opening of Genesis as it manages to conform to modern theories of creation, but does it in language devoid of the terms needed for modern scientific description. However, the Bible is not attempting to ‘do science’. What the author of Genesis is striving for, is to ‘do God’. We should look at Genesis to understand the meaning of creation, not the physics; the ‘why’ not the ‘how’.
The instigation for creation is God saying, “Let there be light”. God, of course, did not ‘speak’ in the conventional sense of the word. When we talk of someone who is totally honest and trustworthy and does what they promise, we say their actions are as good as their words. When referring to God, the Bible often freely interchanges the idea of God speaking and acting.  God’s ‘Word’ is as much what God does as what he says. God said, “Let there be light”; and there was light. And God saw that the light was good; and God separated the light from the darkness. 
So right at the beginning of the Bible we get this identification of Light as Good.
After Adam and Eve are ejected from the Garden of Eden in chapter 3, God keeps re-appearing in the narrative – often as a bright light. I am thinking of Moses and the burning bush – which, of course looked as if it was burning but wasn’t – it was shining with the Glory of God – the Shekinah Glory. I am thinking of the pillar of cloud by day and of fire by night which went ahead of the Israelites in the desert after the Exodus from Egypt. I am thinking of Moses’s face shining so brightly after his encounters with God that he had to wear a veil. I am thinking of how the Glory of God filled the temple at its dedication by Solomon, so that all the priests had to get out of the building. And I’m thinking of Luke, chapter 2, when the shepherds were sitting on a hillside at night, an angel appeared and ‘the Glory of the Lord shone upon them’.  So light is associated with the presence of God. 
Light is also used as a metaphor for knowledge; seeing as a metaphor for understanding or wisdom. Light enables us to see, in darkness we are blind. Jesus talks of the Pharisees as being ‘blind guides’ – of the blind leading the blind so that both fall into the ditch. He talks of those who have eyes to see but see not. When we have been struggling to understand something, we sometimes get it ‘in a flash’ – or we say something like “Ah! Now I see it”. We have ‘light-bulb moments’ and the flowering of the European intellectual movement from the late 17th century we call ‘The Enlightenment’. 
But the most important metaphors based in this passage are the descriptions of Jesus himself as the Word of God and as the Light of the World.
When the writers of the gospels started to put down their accounts, they had to decide where to start. Matthew, the author who focusses most on Jewish heritage and history, starts with the genealogy of Jesus, beginning with Abraham. Mark starts with the prophesy of Isaiah about John the Baptist and Luke with the birth of John the Baptist. John, however, starts where the Hebrew scriptures start, with creation. And he deliberately re-casts the first 5 verses of Genesis in the light of his understanding of Jesus. In the famous passage we read on Christmas morning he says:  
In the beginning was the Word, and the Word was with God, and the Word was God. 2 He was in the beginning with God. 3 All things came into being through him, and without him not one thing came into being. What has come into being 4 in him was life,[a] and the life was the light of all people. 5 The light shines in the darkness, and the darkness did not overcome it.
For Mark, there is no need to reference the virgin birth and, like John, he bypasses the birth narratives completely. Instead, they both look to the baptism of Jesus by John as the primary confirmation of the linkage of the earthly Jesus to God. I find verse 10 a little confusing – too many uses of the male pronoun. “And just as he was coming up out of the water, he saw the heavens torn apart and the Spirit descending like a dove on him.” I have to compare with the other gospels to understand: “And just as he – Jesus - was coming up out of the water, he – John - saw the heavens torn apart and the Spirit descending like a dove on him - Jesus.” Then God says: “You are my Son, the Beloved; with you I am well pleased.”  This picture of the 3 persons of the Trinity, together at the start of Jesus’s earthly ministry, is where Mark starts his account. But to understand the image we need to go back to Genesis, before time and space, where God the Father is present, as is the Holy Spirit – often described as the breath or wind of God - and the Word that God the Father speaks, through whom all things were created. That Jesus is the Word of God and the Light of God is spelled out for us in John’s gospel, but Mark leaves us to work it out for ourselves through the rest of his gospel. 
From the moment of creation in Genesis 1, 1-5, the history of the universe then unfolds. The Hebrew scriptures focus particularly on the history of one group – the people of Israel. But as we read through not just books of history, but the rest of the Old Testament, and particularly the prophets, we are led to see a trajectory to the story and that things are going to come to a focal point at some time in the future. The description of John the Baptist is very much in the tradition of the prophets of the Old Testament. Not only is he the last of those prophets, he is, in himself, the fulfilment of prophesy and the culmination of the prophet tradition. As the three persons of the Trinity come together again in a specific point in space and time at the baptism of Jesus, we come to that focal point in history; there is, in effect, a second ‘singularity’. A second process of creation has started – which will result in a new heaven and a new earth - as described at the close of the Book of Revelation. We are now on that journey. We are to enjoy that original creation, but also work within it, and with the Word of God who created it in the first place, towards building that new creation.