Hadith 180
جاء وفد ثقيف الي رسول الله صلى الله عليه وسلم فقالوا يا رسول الله ! الايمان يزيد و ينقص؟ قال : لا ، الايمان مكمل فى القلب زيادته كفر و نقصانه شرك
"The delegation of Thaqif came to the Messenger of Allah (peace be upon him) and asked: 'Does faith increase and decrease?' He (peace be upon him) replied: 'No, faith is complete in the heart; increase in it is disbelief and decrease in it is polytheism.'"
