Is committing sins an indicator of corruption or suspicion in one's faith?

Good morals are an integral part of religion and Islam, as stated in the Almighty's saying: (وَإِنَّكَ لَعَلَى خُلُقٍ عَظِيمٍ) "And indeed, you are of a great moral character." Ibn Abbas interpreted "great moral character" as Islam. Behavior and morals are closely linked to creed. A Muslim who believes that Allah is watching him is driven by his creed to do what Allah loves and to abandon what He dislikes. Furthermore, faith motivates good deeds and prevents sins. Belief in Allah's divine decree and destiny prevents bad morals like discontent and calls for patience and contentment. Islamic law has linked many acts of obedience to faith in Allah and the Last Day, and has warned against sins because of it. The Prophet, peace and blessings be upon him, clarified that corruption of belief leads to corruption of morals and deeds.