In his book "Mere Christianity," C.S. Lewis addresses the nature of love and promises, emphasizing that a promise made in love commits one to remain faithful regardless of changing feelings. He argues that true commitment goes beyond mere emotional states and is rooted in deliberate actions and decisions. Love may inspire promises, but real integrity involves upholding those promises even when feelings wane.

Lewis highlights the impossibility of promising to sustain a particular emotional state, using the analogy of pledging to never experience headaches or constant hunger. Authentic commitment is about following through on actions and choices, demonstrating loyalty and dedication despite the ebb and flow of emotions. Ultimately, he suggests that the essence of love is found in our willingness to act faithfully, not just to feel a certain way.