Firstly, it highlights the dichotomy between the heart and the mind. The heart often represents emotions, desires, and passions, while the mind symbolizes logic, reason, and rationality. When these two aspects of the self are in conflict, it can lead to a state of unrest and sleeplessness.
Secondly, the quote implies that this inner battle is intense and powerful. It's not a simple disagreement but a full-blown war, signifying the profound struggle between our emotions and our thoughts, which can be emotionally draining and mentally exhausting.
In essence, this statement speaks to the universal human experience of grappling with conflicting emotions and thoughts, especially during moments of deep introspection or decision-making. It portrays the profound impact of such inner conflicts on our ability to find peace and rest, highlighting the complexity of the human psyche.