And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.
Genesis 1:5
"God, through the 'pen' of Moses, is being redundant for redundancy's sake. God is going out of His way to tell us that the 'days' of Creation were literal solar days. He has used the word yôm and combined this with a number and the words' morning' and 'evening.' God has communicated the words of Genesis 1 in a specific manner, so that the interpreter could not miss His point. God could not have communicated the timing of creation more clearly than He did in Genesis 1." Stambaugh, 1991