MULMANTRA: THE FUNDAMENTAL CREED OF SIKHISM
The best definition that any Sikh can give regarding the concept of God in Sikhism is to quote the Mulmantra the fundamental creed of Sikhism, which occurs at the beginning of Sri Guru Granth Sahib.
It is mentioned in Sri Guru Granth Sahib, volume 1 Japuji, the first verse:
"There exists but one God, who is called The True, The Creator, Free from fear and hate, Immortal, Not begotten, Self-Existent, Great and Compassionate."
Sikhism is a monotheistic Religion
Sikhism enjoins its followers to practise strict monotheism. It believes in only One Supreme God who is, in the unmanifest form, called Ek Omkara.
In the manifest form He is called Omkara and has several attributes such as:
Besides Sikhism being strictly monotheistic, it also does not believe in Avataravada the doctrine of incarnation. Almighty God does not incarnate Himself in what is known as Avatara. Sikhism is also strongly against idol worship.
Guru Nanak was influenced by the sayings of Sant Kabir so much that several chapters of Sri Guru Granth Sahib contain couplets of Sant Kabir.
One of the famous couplets of Sant Kabir is:
mein sumirana sabh karein
times of trouble, God is remembered by all
Compare this with the following verse of the Quran:
some trouble toucheth man,
scriptures therefore emphasise monotheism and God-consciousness.