What is the ruling on those who say, "O Ali" and "O Hussein" when rising or carrying something, or "Labbayk Ya Zahra" and "Labbayk Ya Hussein," or swear by Ali or Hussein or Zahra, or say: "I seek Your forgiveness, O Hussein"?

Calling upon the dead when doing something is a form of seeking their aid or succor, and it is shirk (definition) (polytheism). Saying "Labbayk Ya So-and-So" is permissible for the living if the person is someone whose call it is permissible to answer. However, using it for the dead is not correct except metaphorically, and some scholars, like Sheikh Al-Fawzan, have prohibited it. Swearing by other than Allah, even if it is a prophet, is not permissible and is shirk of wording. Seeking forgiveness for sins and asking for repentance is not permissible except from Allah alone. Seeking it from other than Him is shirk, as Allah Almighty says: "And who is more astray than he who invokes besides Allah those who will not respond to him until the Day of Resurrection." (Quran 46:5). As Sheikh al-Islam Ibn Taymiyyah clarified, supplicating to other than Allah and seeking their aid is not permissible; only Allah alone should be supplicated, and forgiveness is not used except with Allah the Almighty.