心中无敌无敌之心
[xīn zhōng wú dí wú dí zhī xīn]
'In the heart, there is no enemy, therefore having an unbeatable mind,' indicating profound self-confidence or the concept that all battles are internal and if one conquers oneself, one remains unconquered in the outer world. This can refer to mental fortitude, resilience, a philosophy of pacifism, or an unyielding fighting spirit. It encapsulates the belief in inner strength to overcome external adversities.