They called out to Him, all Israel and then He sent Moses to deliver them.
I can't remember who said that anymore.
That man from Wales prayed 6 hours a day or more and almost all Wales got saved.
2 Chronicles 7, He can do things without prayer like shut up the heaven, I think this text is very clear, 'He can do nothing unless His people pray' is not true, but in order to restore we need to pray:
13 When I shut up heaven and there is no rain, or command the locusts to devour the land, or send pestilence among My people, 14 if My people who are called by My name will humble themselves, and pray and seek My face, and turn from their wicked ways, then I will hear from heaven, and will forgive their sin and heal their land.15 Now My eyes will be open and My ears attentive to prayer made in this place.