Tawhid, The Unity of God from the Holy Qur'an

Surah Al-Baqarah, n.2

وَإِلَٰهُكُمْ إِلَٰهٌ وَاحِدٌ ۖ لَا إِلَٰهَ إِلَّا هُوَ الرَّحْمَٰنُ الرَّحِيمُ

And your Allah is one Allah! there is no god but He; He is the Beneficent, the Merciful (2:163)[^1]

وَمِنَ النَّاسِ مَنْ يَتَّخِذُ مِنْ دُونِ اللَّهِ أَنْدَادًا يُحِبُّونَهُمْ كَحُبِّ اللَّهِ ۖ وَالَّذِينَ آمَنُوا أَشَدُّ حُبًّا لِلَّهِ ۗ وَلَوْ يَرَى الَّذِينَ ظَلَمُوا إِذْ يَرَوْنَ الْعَذَابَ أَنَّ الْقُوَّةَ لِلَّهِ جَمِيعًا وَأَنَّ اللَّهَ شَدِيدُ الْعَذَابِ

And there are some among men who take for themselves objects of worship[^2] besides Allah, whom they love as they love Allah, and those who believe are stronger in love for Allah and O, that those who are unjust had seen, when they see the chastisement, that the power is wholly Allah's and that Allah is severe in requiting (evil). (2:165)

[^1]: O.T. ‘Hear O’ Israel: Our Lord is our God is one Lord’ Deut 6:4. See also: Tim, 2:5; John 20:17; Mat 4:10. All apostles including Jesus taught only the Unity of God and never the Trinity.

[^2]: In substance