Where is the instruction to the church to pursue or pray for a revival?

You’re asking questions of a modern historical nature that are not particularly relevant to the New Testament. What I mean is that the term doesn’t occur in the New Testament; I suspect it was popularized by Charles Finney. I tend to take a different view of things; basically, what the NT affirms about how God changes hearts—both individually and corporately. Thus, rather than worry about defining this thing, maybe we ought to be more concerned about living for the Lord individually—something that will surely impact others.