Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
quran:6:19

Say, "What thing is greatest in testimony?" Say, "Allah is witness between me and you. And this Qur'an was revealed to me that I may warn you thereby and whomever it reaches. Do you ˹truly˺ testify that with Allah there are other deities?" Say, "I will not testify ˹with you˺." Say, "Indeed, He is but one God, and indeed, I am free of what you associate ˹with Him˺."  

When they said to the Prophet (s), ‘Bring us someone to testify to the truth of your prophethood, for the People of the Scripture have denied you’, the following was revealed: Say, to them: ‘What thing is greatest in testimony?’ (shahādatan: this is for specification, and is derived from the ˹implied˺ subject of the sentence). Say: ‘God — even if they do not say this, there is no other response — He, is Witness between me and you, to my truthfulness; and this Qur’ān has been revealed to me that I may warn you, ˹that I may˺ make you fear, O people of Mecca, thereby, and whomever it may reach (wa-man balagha: this is a supplement to the ˹suffixed˺ pronoun ˹‘you’˺ of undhira-kum, ‘I may warn you’), that is to say, whomever among men and jinn the Qur’ān may reach. Do you indeed bear witness that there are other gods with God?’ (this interrogative is meant as a disavowal). Say, to them: ‘I do not bear witness’, to this. Say: ‘He is only One God, and I am innocent of what you associate’, with Him of idols.
القرآن:٦:١٩

قُلْ أَيُّ شَيْءٍ أَكْبَرُ شَهَادَةً ۖ قُلِ اللَّهُ ۖ شَهِيدٌ بَيْنِي وَبَيْنَكُمْ ۚ وَأُوحِيَ إِلَيَّ هَٰذَا الْقُرْآنُ لِأُنْذِرَكُمْ بِهِ وَمَنْ بَلَغَ ۚ أَئِنَّكُمْ لَتَشْهَدُونَ أَنَّ مَعَ اللَّهِ آلِهَةً أُخْرَىٰ ۚ قُلْ لَا أَشْهَدُ ۚ قُلْ إِنَّمَا هُوَ إِلَٰهٌ وَاحِدٌ وَإِنَّنِي بَرِيءٌ مِمَّا تُشْرِكُونَ  

ونزل لما قالوا للنبي ﷺ إئتنا بمن يشهد لك بالنبوة فإن أهل الكتاب أنكروك {قل} لهم {أيُّ شيءٍ أكبر شهادة} تمييز محول عن المبتدأ {قل اللهُ} إن لم يقولوه لا جواب غيره، وهو {شهيد بيني وبينكم} على صدقي {وأوحي إليَّ هذا القرآن لأنذركم} أخوفكم يا أهل مكة {به ومن بلغ} عطف على ضمير أنذركم أي بلغة القرآن عن الأنس والجن {أئنَّكم لتشهدون أن مع الله آلهة أخرى} إستفهام إنكاري {قل} لهم {لا أشِهدُ} بذلك {قل إنما هو إله واحد وإنني بريء مما تشركون} معه من الأصنام.