The Biblical calendar is derived primarily through the genealogies found in the book of Genesis. From Adam all the way down to Abraham, Isaac, and Jacob. Then down through the 430 year stay in Egypt, followed by the period of the judges, and then the kings. The calendar is then followed to the birth of Christ (7 BC) and on the New Testament side until the death of Christ on the cross (33 AD). Given this framework, we see wonderful harmonious connections between major Biblical events.
Take the creation date for example, from 11,013 (creation) to the flood (4990) equals 6,023 years. And from the flood (4990) to the cross equals 5,023 (cal.) years. Not only that, but other key dates, established through the Biblical calendar also fall in wonderful harmonious fashion. Such as the beginning of king David's reign (1007 BC) to the birth of Christ (7 BC) equaling an exact 1,000 years. Or, the death of David, that great type of Christ, and the laying of the temple foundation (967 BC) to the death of Christ on the cross (33 AD) equaling an exact 1,000 (cal.) years.
Many examples could be given which show forth an overall cohesiveness and fit from one date to another date. Given this, how is it possible for the Biblical calendar to be "all wrong" as some say. According to bishop Usher and the calendar the churches go by the Biblical calendar of history uncovered by Mr. Camping (by God's grace) should be thousands of years off the mark. And yet we find these type of perfect time path fits. We also find that the dates for Solomon's reign and death (971 to 931 BC) match up very well with secular sources, differing by only a year or so. Again, how is it possible for the Biblical calendar of history to come down thousands of years from 11,013 BC and give an accurate date for Solomon's reign--if its thousands of year off course?
The inner cohesiveness we see with the Biblical calendar of history reveals it was designed by an intelligent Being. It reveals a map for the time line of this world that is not random, and happenstance in any way; but instead is very deliberate and calculated and orderly.
Just as scientists have learned about the complexity of DNA and the wonderful inner workings of the body and all things, revealing the creation itself had to be designed by an intelligent Designer (God). So too does the cohesiveness and inner workings of the Biblical calendar of history reveal that a Master Designer (God) is at work orchestrating all historical events to fit into a wonderful and glorious pattern in which He has laid out His salvation and judgment programs.
But just as natural men of the world reject the idea of a Grand Designer (God) creating all things, and opt instead for the unorganized and ridiculous notion that everything happened by chance, so too do natural minded men reject the wonderful harmony of the Biblical calendar and opt for some lesser thing that shows forth no inner calendar relationships at all. They opt for a calendar that has no cohesiveness or internal proofs of any kind. In fact, Usher's calendar has contradictions and errors that show it to be untrue and incorrect. The true Biblical calendar of history stands alone and when pondered it reveals the brilliant mind of an orderly God behind it.