Who made Guru Nanak Dev a Guru? and Why?

Respected Brother/Sister,
Waheguru ji ka Khalsa, Waheguru ji ki Fateh!

In reply to your question the undersigned wants to say that first Guru Person Guru Nanak Sahib was given a mission by Akalpurakh to connect the entire humanity directly with Him and teach a life style, which had nothing to do with superstitions, hypocrisy and rituals.

As per Gurbani, Akalpurakh and Guru are embodiment of each other. Therefore, Akalpurakh gave first Guru Person Guru Nanak Sahib lot of strength to travel far and wide, which are called Udasis, to spread and fulfill the mission given to him by Akalpurakh.

During these travels, he touched the lives of a large number of persons, who were ‘seekers of truth ‘. They became Guru Nanak Sahib’s Sikhs and treated him as their Guru. This is how he became to be called Guru.

Hope it helps. If you have any further questions please do ask and if you find any deficiencies please point out the same to enable the undersigned to improve in future.

Regards,
Your Brother
——————————-
ਗੁਰੁ ਪਰਮੇਸਰੁ ਏਕੋ ਜਾਣੁ ॥ ਜੋ ਤਿਸੁ ਭਾਵੈ ਸੋ ਪਰਵਾਣੁ ॥੧॥ ਰਹਾਉ।। (ਪੰਨਾ 864)
ਹੈ।੩।

ਹੇ ਭਾਈ! ਗੁਰੂ ਦੀ ਵਡਿਆਈ ਬਿਆਨ ਨਹੀਂ ਕੀਤੀ ਜਾ ਸਕਦੀ। ਗੁਰੂ ਉਸ ਪਰਮਾਤਮਾ ਦਾ ਰੂਪ ਹੈ, ਜੋ ਹਰ ਥਾਂ ਵਿਆਪਕ ਹੈ। ਹੇ ਨਾਨਕ! ਆਖ-ਜਿਸ ਮਨੁੱਖ ਦੇ ਵੱਡੇ ਭਾਗ ਜਾਗਦੇ ਹਨ, ਉਸ ਦਾ ਮਨ ਗੁਰੂ ਦੇ ਚਰਨਾਂ ਵਿਚ ਟਿਕਿਆ ਰਹਿੰਦਾ ਹੈ।੪।੬।੮।