Whole Sort Of Genl Mish Mash
But the next step, a perfectly legitimate question in metaphysics, is what is the nature of God, how did He do it, but once you add God, you are told be many that such questions are off limits.
Naturally, science cannot answer these questions for us. Only revelation, by God's initiative and at His discretion, can answers beyond those of Flew's be ascertained.
I'm not sure who is spouting the "off limits" rhetoric, but I think a more accurate response would be that such answers have not been revealed. Science can ascertain certain Godly attributes (e.g., power and knowledge) but defining his moral attributes requires a careful vetting of revelatory traditions.
"What is the nature of God" (in terms of his substance) and "How did he do it" must ultimately take a back seat to "Why did he do it?" Answers to the "what" and "how" questions might satisfy our intellectual curiosity, but don't answer the questions that are more important to us, especially the "why" questions, which are potentially of eternal significance. A God who is there but silent is more problematic to me than a God who is there and has not only made Himself known to man in space and time, but has also revealed the means by which our separation from the personal God can be remedied.
Take, for example, your daughter. One might ask how a sperm and ovum could result in such a remarkably complex person, how her genes know when to trigger neurological development at certain intervals to enable her to walk, begin to speak, and develop the ability to reason. Science may be able to answer these questions, but what about why she makes you smile when you come home from work, or the pride you feel for her when she says her first complete sentence?
The love God has for His "children" can be known, but not from data gathered from a space telescope or under a microscope. While His moral attributes are evident in our own, they are only known to us through His specific revelation. An important starting point is the factual resurrection of Christ in history. That the resurrection happened is difficult to dispute - why it happened is revealed, and with the answer to that "why" question lies an important answer to Flew's hesitance over the problem of evil (which, in my mind, isn't the real problem - the real problem is the problem of good ... if good is a perfect standard and we have not met it, why would God want us to have any place in His creation to begin with?).