God said (occurs 10 times in Introduction). This begins each day: 3rd day twice; 6th day four times. The second act is also of God (1 Peter 1:23-25). App-5.
be light. become light (as in Genesis 1:2), not the verb "to be". Light not located till 4th day.
was. became, as in Genesis 1:2. It is even so in the New Creation: His Word enters and gives light (Psalms 119:130; 2 Corinthians 4:6).