Charles G. Finney 
Can Two Walk Together Except They Be Agreed? [EPUB ebook] 
A Sermon Preached From Amos 3:3 in the Presbyterian Church at Troy

In the holy Scriptures, we often find a negative thrown into the form of an interrogation. The text is an instance of this kind; so that we are to understand the prophet as affirming that two cannot walk together except they be agreed.
For two to be agreed, implies something more than to be agreed in theory, or in understanding; for we often see persons who agree in theory, but who differ vastly in feeling and practice. Their understandings may embrace the same truths, while their hearts and practice will be very differently affected by them. Saints and sinners often embrace in theory the same religious creed, while it is plain that they differ widely in feeling and practice.
We have reason to believe that holy angels and devils apprehend and embrace intellectually the same truths, and yet how very differently are they affected by them.