Al-Matalib al-'Aliyah 2894 — hadiths 2892–2897

Imam Ishaq bin Rahwayh narrates from Wahb bin Munabbih (may Allah have mercy on him) that he said: "Faith is the leader (guiding from the front), and deeds are the driver (urging from behind), while the self is like a stubborn animal between the two. So when the leader leads but the driver does not drive from behind, this is of no benefit at all; and when the driver drives from behind, the self follows him willingly or under compulsion."
Takhrij and grading: This narration is found in Musnad Ishaq bin Rahwayh (2894); the narrators of its chain are thiqat (trustworthy), and it is the saying of the eminent Successor Wahb bin Munabbih (a maqtu' report).