Worship of Shiv's idol was very common in southern India at that time. There were twelve Shivling temples and six of them were situated in the south. Southern India was also ridden with caste system. Guru Nanak had to visit all such places to show the people the path of Eternal Truth i.e. the worship of Almighty, the Formless. This was superior and fruitful than the worship of the idols.After staying for some time (may be a year) in Sangladeep, the Guru reached Cochin on his wayback journey. There is a Gurdwara at this place to mark the memory of the Guru. Delivering his divine doctrine he passed through Palghat, Nilgiri Hills, Rangapatan and then reached Pandharpur. Saint Nam Dev whose Bani is included in Guru Granth Sahib, passed most of his life at this place. From there he reached Barsi which was the native place of Saint Trilochan whose two Sabads are included in Guru Granth Sahib. From there he passed through Poona, Amarnath, Nasik, Aurangabad and reached Amreshwar where there was famous temple called Onkar Mandir. Here the worship of Shivling (Shiv's idol) was considered as a worship of God. The people considered Sanskrit as the language of the gods and learning of Sanskrit language was considered as an act of holiness.
The Guru preached against the idol worship and stressed that one should only worship One but One God, the Formless. The gospel preached by the Guru at the Onkar Mandir, is included in Guru Granth Sahib as Ramkali Mohalla 1- Dakhni Onkar, page 929.
Then he proceeded to Indaur, Ujjain, Baroda and finally reached Palitana where there was a famous Jain temple. Jaini Sadhus would not take bath for many days thinking bathing killed some life in the water. Here he had discussion with a Jain Sadhu named Ambhi. He explained to the Sadhu that running away from water would not do any religious good but the worship of the Almighty was the only answer.
The Guru went through almost all the famous Hindu pilgrimage places in the area and delivered his message of Oneness of God and to have belief in none other than One Supreme Being only. He visited Somnath, Sudhana, Puri and Dwarka. From Kathiawar through Kachh and Chataur, he reached Ajmer. There was a famous Muslim saint, Khawaza Mai-u-din Chisti, who propagated Islam for about seventy years at Ajmer. It was an annual Muslim gathering to celebrate Khawaza's day when the Guru reached there. He forbade the Muslims from worshipping the Makbras (the tombs of their saints), but asked them to worship only One God.
Passing through Pushker, he reached Gokal Mathura-Bindraban. People were in full preparation for celebrating Lord Krishna's birthday. The Hindus placed Krishna's idol (which they call Thakur) in a small cradle.They were swinging it and were putting all their offerings before the idol. The Guru exposed the futility of idol worship and preached them to worship God, the Formless.
After that he arrived at Delhi and stayed at Majnu da Tilla. There is a Gurdwara at this place at the bank of river Jamna. A Gurpurb of Baisakhi is celebrated at this place every year in April. Thence he went to Panipat where he met a Muslim saint Sheikh Sharf or Taher and urged him to worship only one God, the All- Pervading Divine Spirit instead of worshiping the tombs of the saints.
Passing through Pehwa, he reached Kurukshetra, a place where the famous battle of Mahabharat was fought between the Kauravs and the Pandavs. It was an occasion of solar eclipse when the Guru visited Kurukshetra. Thousands of people including a large number of Brahmans and saints had gathered there. Hindus consider it sacred to go to Kurukshetra at the time of solar eclipse, bathe in the holy tank and give alms to Brahman priests. According to Hindu belief, solar eclipse occurs when sun, the god, is harassed by its enemies, the demons. None is required to eat anything during the eclipse.
The Guru went there to draw attention of the erring Hindu community towards the fact that eclipse was nothing but only a natural phenomenon. The Guru took his seat near the sacred tank and when the sun was eclipsed he began to cook deer which was presented to him by Prince Rai Singh. A big crowd gathered around the Guru, for it was a sacrilege to cook meat. The Brahmans led by Nanu besieged the Guru and were ready to club him to death. The Guru stood up and spoke. His words worked like a magic and the crowd stood spell-bound.
From Kurukshetra the Guru passed through Jind where there is Gurdwara in his memory and then reached Sarsa. Here he met a Muslim saint. The Muslim Pir had great influence over his disciples and he had given them the guarantee of securing a place in heaven for them. In return of such a guarantee, the disciples would bring big offerings in cash and kind to the Pir. The Guru explained to them that in order to get salvation, they should worship One God, the mere offerings would lead them no where.
Sultanpur was about 135 miles north east of Sarsa and after eight years and covering more than six thousand miles on foot, the Guru reached Sultanpur. The elder sister, Bibi Nanki and her husband, and other acquaintances were overjoyed to see him back.
After staying sometimes at Sultanpur, the Guru started towards Talwandi. His father was about 75 years old. There was no postal service in those days. The old parents were waiting for their son to return. At last their son reached home and their joy knew no bounds. People from far and near came to have holy sight of the Guru. They started rejoicing his company again. At that time the Guru's children and his wife were with his in-laws at Pakhokey, a place about 110 miles towards Lahore. So he proceeded to see his wife and children.
Ajita was the Chaudhry (chief) of that village. He had heard about the Guru but he had never met him before. Ajita was so much impressed with the first holy sight of the Guru that he immediately became his disciple.
After starting the habitation of Kartarpur, the Guru started his second travel towards north. He made his first stop at Sialkot, a city about 50 miles east of Kartarpur. After the Muslim invaders established their rule in India, many Muslim faqirs (saints and preachers) also came along with them and these faqirs set up their own centers at different places to preach Islam. Through their missionary work most of the Hindus were converted to Islam. Pir Hamza Ghons was one of those faqirs who set up his center at Sialkot. There lived a Hindu family in that city who did not have any children. Thinking that the Pir had miraculous powers, the head of this Hindu family begged the Pir to bless him with a son. He promised that if a son was born, he would offer him to the Pir. By the grace of God, a son was born, but the man shied away to keep his promise and did not offer his son to the Pir. This enraged the Pir so much that he branded the whole city as full of liars and wanted to destroy it in revenge. In order to accomplish the destruction of the city, he sat in seclusion and undertook a fast of forty days. The people became very frightened and his disciples would not allow any one to come near him.
The Guru sat nearby and asked Mardana to play his rebec and started the Divine Sabad. Upon this the Pir was so much shaken up that he was forced to break his fast. As he listened to the Divine praise and prayer, he calmed down and sat before the Guru. The Guru made the Pir understand that for the mistake of one person, there was no justification of destroying the whole city. Pir Hamza Ghons was touched with the reality and truth.Thus he abandoned his revengeful act of destruction. There is a Gurdwara in honor of the Guru in Sialkot.
From there the Guru proceeded to Jammu and the temple of Vaishnu Devi goddess. Preaching his doctrine of Truth, he passed through Vairi Nag, Kukar Nag and Anant Nag springs and reached Pehalgam and then Amarnath, a place about 90 miles east of Srinagar. The Hindus worshiped Shivling at Amarnath, but the Guru discussed the uselessness of idol worship and asked them to worship one and only one God. A few miles before Amarnath there is a Gurdwara called Matan Sahib.
There lived at Srinagar a very learned Pandit called Brahm Das who always had some camels following him, loaded with volumes of ancient wisdom. This meant that he had the mastery over the knowledge contained in that load of religious books. He learnt that a holy man and a great Teacher had arrived in the valley and that many people had gone to him for his blessing. He first decided to go to him (Guru), but then his pride of knowledge kept him away. One day however, he went to see his friend, Kamal and mentioned to him about a strange visitor (Guru Nanak) in the valley.
Kamal was a devout Muslim and a seeker of Truth. He went to see the Guru without any hesitation. When Kamal got the glimpse of the Guru, he fell on Guru's feet and fainted with joy. As he regained consciousness, he found in his own heart the Light he had been yearning for years. Kamal got the blessing and became Guru's follower. The Guru asked him to settle in the valley of Kurram from where he spread Guru's doctrine to Kabul, Qandhar and Tirah.
After that Brahm Das also came to see the Master. He entered into discussion with the Guru and boasted of his knowledge of ancient wisdom. Seeing his camels loaded with books, the Guru uttered the following Sabad:
On hearing this Brahm Das begged,Forgive me, O holy Guru! I have read sacred books and have acquired academic knowledge of all the six schools of philosophy, but I must confess that I have attained no peace of mind. Pray tell me, how can I get it?
The Guru explained,Academic knowledge breeds pride and pride darkens man's vision. Ego is the greatest barrier and unless a man gets rid of it, he cannot grasp the Truth, and there can be no peace of mind. Brahm Das fell at the feet of the Guru and begged,Save me O Lord! I was in the dark and I am a sinner; bless me with peace. Brahm Das got the blessing and became Guru's disciple. He was entrusted with the task of preaching Sikh faith amongst the people of Kashmir valley.