It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "A person's faith is not complete until he makes an exception (by saying in sha' Allah) in everything he says", or he (peace and blessings be upon him) said: "in all his speech."
Ahmad bin Mani' (may Allah have mercy on him) narrated it in his Musnad; however, according to the hadith scholars there is weakness in its chain because of narrators such as Abdullah bin Sa'id bin Abi Sa'id al-Maqburi and Ma'arik bin Abbad.
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الإيمان والتوحيد / 3008
Hadith Gradingمحدثین:إسناده ضعيف جدًا
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :إسناده ضعيف جدًا. » «أخرجه المعجم الأوسط للطبراني برقم: 7756»