Saheeh Bukhari Hadees 6405
The term Qur’an used is Hudud Allah to tell that there violation is transgressing the boundaries drowned by God. The amount of punishment and intensity of displeasure of God shown determine that a violation is major violation. See the verses, 22:30, 24:2, 5: 38, 4:23 ( in the perspective of the law of inheritance in the verse 4: 11-12)