As Arthur Wallis said in his book "In the Day of Thy Power", that revival involves both the sovereingty of God and the preparedness of man. Before God will send revival, there are certain conditons that have to be met. Here is a brief excert from the book.
"There is an extreme view of the sovereignty of God that argues, "If God wills to send revival it will come. Nothing that we do can effect this, so why need we be concerned?" The word of God and history teach us that such an attitude of indifference and fatalism must be abandoned before revival can be expected. If the blessing comes then we may be sure that somewhere someone has met the conditions and paid the price. Such a view of divine sovereignty ignores the conditions of spiritual preparedness.
There is also an extreme emphasis on spiritual preparedness that ignores the fact of divine sovereignty; it suggests that God is at our beck and call, and that we can have revival any day we care to pay the price, much as we can have electric light the moment we care to turn the switch. The word of God gives us the proper balance by presenting, as here in the first verse of Acts 2, the two aspects side by side. Similarly David declared, "Thy people offer themselves willingly in the day of Thy power" (Ps. 110:3). The day of His power is determined by God alone, and emphasizes His sovereignty; but in that day His people have met the conditions by being ready and willing, which reveals the fact of spiritual preparation. God reminds us of His sovereignty when He declares, "I will cause the cities to be inhabited, and the waste places shall be builded . . . I the Lord have spoken it, and I will do it"; but He adds, "For this moreover will I be inquired of by the house of Israel, to do it for them", reminding us of the conditions that must be fulfilled (Ezek. 36: 33-37).
War is not all attack, but there is a strategic moment for offensive action. The place, the time, and the manner of any attack are of crucial importance in the interests of the campaign as a whole; therefore such matters are not left to the soldier in the fighting line, but are determined beforehand by the supreme commander in the conference room. He alone can see the whole picture and keep his hand upon the whole situation. If, however, the plans made at the highest level are to be carried through successfully, the soldier in the line must be fully prepared for all that is involved. Revival, as, we have seen in the previous chapter, is a strategic attack by God upon the strongholds of Satan. The place, the time, and the manner of working are in the sovereign hands of the Lord the Spirit; but His subordinates, through whom He works, must be spiritually prepared when God's zero hour strikes.
How clearly these two important factors are set forth in the promised rain of Canaan. Divine sovereignty was seen in that the rain was confined to its God-appointed "season", but it was also strictly conditioned by the obedience of the people. "If ye shall hearken diligently unto My commandments which I command you this day, to love the Lord your God, and to serve Him with all your heart and with all your soul, that I will give the rain of your land in its season" (Deut. i x: 13). God declared with equal emphasis and on the same occasion, that if on the other hand they turned aside and served other gods and worshipped them, He would "shut up the heaven, that there be no rain, and that the land yield not her fruit" (verses 16, 17).
How spiritual preparedness, or the absence of it, may influence God's working is vividly illustrated by the visit of the Saviour to Nazareth. "He could there do no mighty work . . . and He marvelled because of their unbelief" (Mark 6: 5,6). What this spiritual preparation involves, and how it may be effected, is a subject so large and so important that it must be considered separately."