Various sacred speeches of respected Shri Guru Nanak Dev Ji scripted in pious Sri Guru Granth Sahib narrate the true account of his meeting with Akaal Purush which proves the fact that God is in human form and He resides in the ultimate abode Sachkhand / Satlok. He is greeted as Param Akshar Purush/ Sat Purush. His name is Kabir Dev. This description has been mentioned in one of the sacred speeches of Shri Nanak Dev Ji in Rag (Raag) Ramkali, First Mehla, Dakhanee, Ongkaar on page no. 929-30 and page no. 1038. 

When God Kabir Saheb met respected Shri Nanak DevJi on the river Bein He provided him true spiritual knowledge and explained how he created the entire universe with his word power. The creation of everything which is between the Sky and the Earth is done by Akaal Purush/Satpurush. He is omnipresent, Omnipotent. It is He who created the eternal world Sachhkhand/Satlok. He created the owner of the twenty-one universes out of an egg called Jyot Swaroopi Niranjan but had to expel him because of the misconduct Niranjan did in that divine Land and was, therefore, later known as Kael/Kaal/Akshar Purush. He is being cursed to eat the grime of one-lakh subtle human bodies every day and produce 1.25 lakh every day. 

The sacred speech of Shri Nanak Ji in Rag (Raag) Ramkali, First Mehla, Dakhanee, Ongkaar being scripted in pious Sri Guru Granth Sahib provides a vivid description of the creation of the twenty-one universes of Brahm-Kaal. He and his wife Goddess Durga gave birth to triple Gods. Shri Lord Brahma Ji is the eldest son, Shri Vishnu Ji is second, and their youngest son is Shri Shiv Ji. During the churning of the ocean the Vedas came out which were obtained to Shri Brahma Ji that were initially given by Akaal Purush to Jyoti Niranjan which glorify the creator God Kabir Saheb and How can He be attained by true worship?. This sacred speech in Raag Ramkali, First Mehla, explains that ‘OM’ is the mantra of the perishable God Akshar Purush. He is the essence of the three worlds - The earth, the Heaven, and the Nether world. This speech glorifies the immortal Param Akshar Purush who dwells deep within the universe. His right way of worship is provided by an enlightened (Tatvadrashi) Saint who preaches to abandon the forced way of worship (Hathyoga Sadhna) and focuses on scriptures based on true worship. 

Let us have a look at what Guru Nanak Dev Ji is trying to explain in Rag (Raag) Ramkali, First Mehla, Dakhanee, Ongkaar scripted in pious Sri Guru Granth Sahib on page no. 929-30 and page no. 1038.  

Sacred Speech of Nanak Ji, Rag (Raag) Ramkali, Mehla 1, Dakhni Ongkaar

(ਰਾਮਕਲੀ ਮਹਿਲਾ 1; ਦਖ-ਨੀ ਓ-ਅੰਕਾਰ) 

Ref: Shri Guru Granth Sahib, Page No. 929-30

Mentioned below is the sacred speech of Guru Nanak Ji in Raag Ramkali Mehla 1

Gurumukhi Vaani:

ਓਅੰਕਾਰਿ ਬ੍ਰਹਮਾ ਉਤਪਤਿ ॥ ਓਅੰਕਾਰੁ ਕੀਆ ਜਿਨਿ ਚਿਤਿ ॥
ਓਅੰਕਾਰਿ ਸੈਲ ਜੁਗ ਭਏ ॥ ਓਅੰਕਾਰਿ ਬੇਦ ਨਿਰਮਏ ॥
ਓਅੰਕਾਰਿ ਸਬਦਿ ਉਧਰੇ ॥ ਓਅੰਕਾਰਿ ਗੁਰਮੁਖਿ ਤਰੇ ॥
ਓਨਮ ਅਖਰ ਸੁਣਹੁ ਬੀਚਾਰੁ ॥ ਓਨਮ ਅਖਰੁ ਤ੍ਰਿਭਵਣ ਸਾਰੁ ॥੧॥
ਸੂਰਜ ਪਦਯ ਕੀ-ਏ ਲਖਹੁ ਜੰਜਾਲਾ। ਲਖ ਰਾਮ ਨਾਮ ਗੁਰਮੁਖ ਗੋਪਾਲਾ॥ || 1 || ਰਹਾਓ.
ਸਾਸੈ ਸਭ ਜਗ ਸਹਿਜ ਆਈ-ਆਈ- ਕਿਸ਼ੋਰ किशोर ਭਵਨ ਇਕ ਜੋਤੀ |
ਗੁਰਮੁਖ ਵਾਸਤ ਪਰਾਪਤ ਹੋਵੈ ਚੁਨ ਲਾਇ ਮਾਨਕ ਮੋਤੀ।
ਸਮਜੈ ਸੋਝੈ ਪਾਰਬ ਬੂਝੈ ਅੰਤਰਿ ਨਿਰੰਤਰ ਸਚਾ॥
ਗੁਰਮੁਖਿ ਦਿਨਖੈ ਸਾਚ ਸਮਾਲੈ ਬਿਨੁ ਸਚਾਏ ਜਗ ਕਾਚਾ॥
ਧਧੈ ਧਰਮ ਧਾਰੈ ਧਰਮਾ ਪੁਰੁ ਗੁਣਕੈ ਮਨ ਧੀਰਾ॥

Transliteration:

Omkaar Brahma utpati |omkaaru kiaa jini chit 
omkaar sael jug bhaye omkaar bed nirmaye 
omkaar sabdi udhre omkaar gurumukhi tare 
onam akhar sunhu bichaaru onam akhru tribhuvan saaru
sun paaday ki-aa likhahu janjaalaa | likh raam naam gurmukh gopaalaa. ||1|| rahaao.
sasai sabh jag sahj upaa-i-aa teen bhavan ik jotee |
gurmukh vasat paraapat hovai chun lai maanak motee |
samjhai soojhai parh parh boojhai ant nirantar saachaa |
gurmukh daykhai saach samaalay bin saachay jag kaachaa. ||2||
dhadhai dharam dharay dharmaa pur gunkaaree man dheeraa.

{There is only one line in Guru Granth Sahib}

ओमकार ब्रह्मा उत्पति || ओमकारू किआ जिनी चित ||
ओमकार सैल जुग भये ||  ओमकार बैदा निरामए ||
ओमकार सबदी उधारे || ओमकार गुरुमुखी तारे ||
ओनमा अखारा सुनहु बिचारु || ओनामा आखरू त्रिभुवना सारू।।
सुण पाण्डे किया लिखहु जंजाला, लिख राम नाम गुरु मुख गोपाला || 1 || रहाऊ ||
ससै सभ जग सहज उपाइया, तीन भवन इक जोति |
गुरु मुख वस्तु परापत होवै, चुण लै मानक मोती |
समझै सूझै पड़ि-पड़ि बुझै अति निरंतर साचा |
गुरु मुख देखै साच समाले, बिन साचे जग काचा || 2 ||
धधै धरम घरे धरमा पुरि गुण करी मन धीरा |

{गुरु ग्रन्थ साहेब में एक ही पंक्ति है} 

Translation: From Ongkaar (OM), the One Creator God of only twenty-one universes (Jyoti Niranjan-Kaal), Brahma Ji was created. He kept Ongkaar (Shri Brahma Ji) in his consciousness. From Ongkaar (OM), the mountains and the ages were created (in twenty-one universes). Ongkaar (OM) produced the Vedas (received to him by Param Akshar Brahm and later obtained to Shri Brahma Ji after churning of the ocean). Ongkaar (OM) saves the world through the Shabad. Ongkaar saves the Gurmukhs. Listen to the Message of the Perishable Creator Lord (Kaal). The Perishable Creator Lord (Brahm-Kaal) is the essence of the three worlds (The earth, Heaven, and the Nether world). ||1|| Listen, O Pandit, O religious scholar, why are you writing about worldly debates? As Gurmukh, write only the Name of the Lord, the Lord of the World (Akaal Purush). ||1||Pause|| Sassa: He (Param Akshar Purush/Sat Purush) created the entire universe with ease; His One Light pervades the three worlds. Acquire a true Guru and obtain the real thing (True salvation mantras); gather the gems and pearls (true devotion of Satpurush). If one understands, realizes, and comprehends (about Akaal Purush) what he reads and studies (one is uplifted by doing Jaap of OM), in the end, he shall realize that the True Lord (Akaal Purush/Satpurush) dwells deep within the universe. The Gurmukh (true devotee) sees and contemplates the True Lord; without the worship of the True Lord (God Kabir Saheb), the world is false (captivated by Trigun Maya). ||2|| Dhadha: Those who enshrine Dharmic faith (Take initiation) and dwell in the City of Dharma are worthy; their minds are steadfast and stable.

Meaning: In the aforesaid sacred speech, Shri Nanak Ji is saying that Brahma Ji was born from Omkaar i.e. Jyoti Niranjan (Kaal). After wandering for many yugas, Omkaar (Brahm) produced Vedas at the destined duration, which was later obtained by Brahma Ji. Only the ‘OM’ mantra is the actual mantra for the devotion of the three loks. One is uplifted by doing Jaap of this ‘OM’ Shabd after taking updesh from a Complete Saint i.e. by acquiring a real Guru. Param Akshar Purush/Shabad Swaroopi Ram created the entire universe. His body is highly effulgent. A true devotee by chanting true salvation mantras attains the eternal world ie. Satlok/Sachkhand.

Important: Shri Nanak Ji has given a secretive description of the three mantras (Om + Tat + Sat) at several places. Only a Complete Sant (Tatvadarshi) can understand this and the method of the Jaap of the three mantras is explained only to the Updeshi (follower, disciple).

Another sacred speech by Shri Nanak Dev Ji mentioned in pious Sri Guru Granth Sahib on Page no. 1038 is described below:

Shri Guru Granth Sahib, Page no. 1038

ਊਤਮ ਸਤਿਗੁਰ ਪੁਰਖ ਨਿਰਾਲੇ ॥ ਸਬਦਿ ਰਤੇ ਹਰਿ ਰਸਿ ਮਤਵਾਲੇ ॥
ਰਿਧਿ ਬੁਧਿ ਸਿਧਿ ਗਿਆਨੁ ਗੁਰੂ ਤੇ ਪਾਈਐ ਪੂਰੈ ਭਾਗਿ ਮਿਲਾਇਦਾ ॥੧੫॥
ਸਤਿਗੁਰ ਤੇ ਪਾਏ ਵੀਚਾਰਾ ॥ ਸੁੰਨ ਸਮਾਧਿ ਸਚੇ ਘਰ ਬਾਰਾ ॥
ਨਾਨਕ ਨਿਰਮਲ ਨਾਦੁ ਸਬਦ ਧੁਨਿ ਸਚੁ ਰਾਮੈ ਨਾਮਿ ਸਮਾਇਦਾ ॥੧੭॥੫॥੧੭॥

Transliteration:

Uttam Satguru purush niraale, sabdi rate hari ras matvaale 
Ridhi, budhi, sidhi, giaan guru te paaiye, poore bhaag milaaida (15)
Satguru te paaye bichaara, sun samaadhi sache gharbaara 
Nanak nirmal naadu sabad dhuni, sachu ramae naami samaaida (17) 5 17

उतम सतगुर पुरख निराला | सबद रटे हर रस मत मतवलय |
रिधि, बुधि, सिद्धि, गियान गुरु ते पाइये,  ग़रीब भग मिल्गा-इदा || 15 ||
सतगुर तैं पा-ऐ वीचरा | सुन्न समदह सच्चाय घर बारा |
नानक निर्मल नाद सबद धुन सच रामय नाम समा-इड़ा। || 17 || 5 || 17 ||

Translation: The True Guru (Tatvadarshi Saint) the Primal Being, is unprecedented. Attuned to the Word of the Shabad (Naam Jaap), He does not tell to do forced worship (Hathyoga). Wealth, miraculous spiritual powers, and spiritual wisdom are obtained from the Satguru; through perfect devotion, they are received. ||15||. From the True Guru, contemplative meditation (True worship) is obtained. And then, one dwells with the True Lord in His celestial home (eternal world Sachhkhand/Satlok), the Primal State of Absorption (attaining Salvation) in Deepest Samadhi. O Nanak, the immaculate sound current of the Naad (Saarnaam), and the Music of the Shabad (SaarShabad) resound; one merges into the True Name of the Lord (attains that blissful abode Sachkhand). ||17||5||17||

Meaning: The aforesaid sacred speech says that the Saguru who imparts real knowledge is unique. He only tells to chant the Naam mantra and does not teach any other Hathyoga Sadhna (forced way of worship). Even if you want wealth, position, wisdom, or the power of bhakti, then also, only a Complete Saint can fully provide the knowledge of the path of true bhakti. Such a Complete Saint is found with great fortune. Only that Complete Saint will tell that God has already created our real home (Satlok) in the Sunn (vacuum place) above. In that place, the sound of the real Saarnaam is going on. One can achieve that blissful state, which means, can reside in that real happiness-giving place by the Saar Shabd of the Eternal God, and not by other Naam and incomplete gurus.

Conclusion

The unprecedented Satguru who met respected Shri Nanak Dev Ji in the form of ‘Jinda Baba’ was none other than Almighty KavirDev who met him on the river Bein and explained to him the entire creation of the universe and how were the souls trapped in the web of Butcher Brahm-Kaal (explained in Raag Ramkali, First Mehla). The same ‘Jinda Baba’ ie. Akaal Purush / Satpurush Kabir Saheb has descended yet again on earth in the form of great Tatvadarshi Saint Rampal Ji Maharaj who is providing scriptures based true worship and giving the secret coded salvation mantras (OM-Tat-Sat) which were provided to respected Shri Nanak Dev Ji chanting which he became the permanent resident of the eternal world Sachhkhand/Satlok. Identify God and take His refuge to attain emancipation (Moksha).