When the builders are working sometimes they wait while something dries or sets. A Cook may be preparing a splendid sitting and at times waits while the pots simmer. The Fourth day is perhaps a little like those. Neither of such artisans as they say “take their eye off the ball” during these periods, a lesson all trainees learn, sometimes at a cost.
From our modern perspective not only can we note plants are made first, but in addition have another day to increase and function before animal life. The contribution of plants to atmospheric quality is now known and a realistic extra day is given plants to do the job. [carbon removal]
The biomass increases, that is the amount of material which either is living or was living (humus and locked carbon). The air may be good but low in oxygen but this changes over the course of the Fourth Day. Care must be taken as the Nature system is set running while only half is installed.
So what about the criticism that light has been made twice? Firstly note the ancients would have seen the apparent contradiction. It is so very obvious, if it is a contradiction it cannot be new. They still passed it down in faith, so how might they have rationalised it? It is easy to visualise the light coming to be in a foggy situation, ancient mariners would know this at sea and hill farmers in low cloud. You had light but could not see the sources as discs in the sky. They would make sense of it as increased clarity.
There is an intention of God that is non functional until the Fourth Day. Consider you are sent a present, the time the sender prepares the gift and the time of receipt/appreciation can be separated by a long period. The gift was to be, “able to use the sky for time measurement”. This gift arrived on the Fourth Day.
It was also the sign the plants had done the atmospheric job.
Termed in the account only as lights without names, two reasons;
1/... God said what they were for, and would probably let Man name them.
2/... Makes clear to ancient believers these are not persons but things of service.
Little boat: can identify the light sources as objects and [planetarium] night sky, we tried the sextant out too. The air invigorates.
We continue and not only that, we; count darkness as day if the Sun has not yet set and count light as night if it has set, we clock missions into space by Earth time, now we have set one time as Universal Time so all Nations can match time. For what God intended, we have found it very useful indeed.