"I said: 'O Messenger of Allah, which sin is most grievous?' He said: 'Setting up a rival to Allah while it is He that created you.' I said: 'Then what?' He said: 'Killing your child so that he will not eat with you.' I said: 'Then what?' He said: 'Committing adultery with your neighbor's wife.'"
Sunan an-Nasa'i Book 37, Hadith 49
← Previous Hadith "I said: 'O Messenger of Allah, which sin is the most grievous?' He said: 'Setting up a rival to Allah while it is He that has created you.' I said: 'Then what?' He said: 'Killing your child for fear that he may eat with you.' I said: 'Then what?' He said: 'Committing adultery with your neighbor's wife.'"

Sunan an-Nasa'i Book 37, Hadith 48 Next Hadith → "I asked the Messenger of Allah , which sin is most grievous?" He said: "Shirk, setting up a rival to Allah, committing adultery with your neighbor's wife, and killing your child for fear of poverty, and that he may eat with you." Then 'Abdullah recited the Verse: "And those who invoke not any other Ilah (god) along with Allah."

Sunan an-Nasa'i Book 37, Hadith 50