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.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
quran:2:138 –

˹And say, "Ours is˺ the religion of Allah. And who is better than Allah in ˹ordaining˺ religion? And we are worshippers of Him."  

The mark of God (sibghata’Llāhi: a verbal noun reaffirming the earlier āmannā, and it is in the accusative, because of the verbal construction implied, that is to say, sabaghanā’Llāhu, ‘God has marked us’): this denotes His religion, the one towards which He made human beings naturally inclined, as it leaves its mark on a person, in the same way that a dye leaves its mark on a garment; and who has, that is, none ˹has˺, a better mark (sibghatan, ‘marking’, is for specification) than God? And Him we worship: the Jews said to the Muslims, ‘We are the people of the first Book and our direction of prayer (qibla) is more ancient, and prophets were never sent from among the Arabs; if Muhammad were a prophet, he would have been one of us’. Thus, the following was revealed:
القرآن:٢:١٣٨ –

صِبْغَةَ اللَّهِ ۖ وَمَنْ أَحْسَنُ مِنَ اللَّهِ صِبْغَةً ۖ وَنَحْنُ لَهُ عَابِدُونَ  

{صِبْغَةَ الله} مصدر مؤكد لآمنا ونصبه بفعل مقدر، أي صبغنا الله والمراد بها دينه الذي فطر الناس عليه لظهور أثره على صاحبه كالصبغ في الثوب {ومن} أي لا أحد {أحسن من الله صبغة} تمييز {ونحن له عابدون} قال اليهود للمسلمين نحن أهل الكتاب الأول وقبلتنا أقدم ولم تكن الأنبياء من العرب ولو كان محمد نبيا لكان منا فنزل.