Struggle [mujaahadah] means restraining the nafs from its desire for any activity other than `ibaadah.
Al-Qushayri relates from his shaykh, Abu `Ali al-Daqqaaq: “Whoever is not a person of mujaahadah at the beginning, will never encounter the perfume of this Path.”
Abu `Amr ibn Bujayd said: “Whoever finds his religion to be precious for him, will pay little heed to his nafs.”
Al-Qushayri said: “The basis of struggling with the nafs is to wean it from familiar things, and to force it away from its whims. The nafs has two qualities: plunging into pleasures, and refraining from acts of obedience. Mujaahadah, therefore, is made against these tendencies.”
[132/Chapter: The one who struggles against his nafs, for the obedience of Allaah, the Glorious and Majestic]