The great Sufi Shaykh Al-Junayd al Baghdadi (May Allah be pleased with him) said:

"Those who have striven against their desires and repented for God's sake, shall be guided to the ways of sincerity. One cannot struggle against his enemy outwardly (i.e. with the sword) except he who struggles against these enemies inwardly. Then whoever is given victory over them will be victorious over his enemy, and whoever is defeated by them, his enemy defeats him."