The question/claim: "A black cat crossing your path, an owl hooting, Tuesday, the number 13, walking under a ladder are unlucky — is this a religious belief?"
What does the Qur'an say? — it rejects omen-taking (tatayyur)
The Qur'an explicitly rejects treating an event/creature/day as an omen; luck does not reside in objects:
"…When evil struck them, they would take it as a bad omen from Moses and those with him. Surely their omen is only with God (their own deeds), but most of them do not know." (7:131)
"(Ṣāliḥ's people) said: We see an evil omen in you and those with you. He said: Your omen is with God; rather you are a people being tested." (27:47)
"They said: Indeed we see an evil omen in you…" — (the messengers:) "Your omen is with yourselves. Is it because you were reminded? Rather you are a transgressing people." (36:18-19)
The principle the Qur'an sets
- Tying misfortune to an object, animal, day or number is the pre-Islamic attitude the Qur'an criticises.
- What befalls a person relates to their own deeds and God's decree (36:19: "your omen is with yourselves") — not to a black cat or an owl.
An honest limit
- Certain: the Qur'an explicitly rejects tatayyur, presenting it as a stance of the deniers.
- Cultural: black cats, owls, Tuesday, 13, ladders, broken mirrors — these originate in folk beliefs and the traditions of various cultures (some modern, Western in origin); they are not a ruling of the religion.
Conclusion: belief in bad luck is the pre-Islamic / cultural attitude the Qur'an openly rejects. A faithful stance is to see both good and ill as from God and to take no omens.
Source: Qur'anic verses (M. Okuyan meal). Built on the Qur'an's explicit rejection of omen-taking (tatayyur); not a fiqh fatwa.