The number "eight" seems commonly to be associated in the Bible with a new beginning, new life, resurrection, or renewal; "seven" being the number of fullness and rest, with the seven-day week used ever since the week of creation. The Lord Jesus Himself was resurrected, never to die again, on the eighth day--that is, the first day--of the week.
It is significant therefore that eight great spiritual revivals are described in the Old Testament--one each under Moses, Samuel, Elijah, Asa, Hezekiah, Josiah, Ezra, and Nehemiah. It is even more significant, however, that each revival was centered around the Word of God. The first, for example, was based on the giving of the law at Sinai. "And he took the book of the covenant, and read in the audience of the people: and they said, All that the Lord hath said will we do, and be obedient" (Exodus 24:7). Then, much later when "Samuel was established to be a prophet of the Lord. . . . And the word of Samuel came to all Israel," eventually "all the house of Israel lamented after the Lord" (I Samuel 3:20; 4:1; 7:2).
Analysis of all of the other revivals will reveal that they also were based on reception and acceptance of God's Word. The last was under Nehemiah. "And they stood up in their place, and read in the book of the law of the Lord their God one fourth part of the day; and another fourth part they confessed, and worshipped the Lord their God" (Nehemiah 9:3).
There were other ingredients in these revivals, but the Word of God was always the foundation, and there can be no true and lasting revival without it. This is why it is so important in our day, when the need for revival is so desperate, that we first get back to a serious study of the Holy Scriptures, believing and obeying as best we can all that is written therein. HMM