AmbarDhara ji
Here is meaning in essence of Shabad you have quoted.
ਚਉਥੈ ਪਹਰੈ ਰੈਣਿ ਕੈ ਵਣਜਾਰਿਆ ਮਿਤ੍ਰਾ ਹਰਿ ਚਲਣ ਵੇਲਾ ਆਦੀ ॥ਕਰਿ ਸੇਵਹੁ ਪੂਰਾ ਸਤਿਗੁਰੂ ਵਣਜਾਰਿਆ ਮਿਤ੍ਰਾ ਸਭ ਚਲੀ ਰੈਣਿ ਵਿਹਾਦੀ ॥ ਹਰਿ ਸੇਵਹੁ ਖਿਨੁ ਖਿਨੁ ਢਿਲ ਮੂਲਿ ਨ ਕਰਿਹੁ ਜਿਤੁ ਅਸਥਿਰੁ ਜੁਗੁ ਜੁਗੁ ਹੋਵਹੁ ॥ ਹਰਿ ਸੇਤੀ ਸਦ ਮਾਣਹੁ ਰਲੀਆ ਜਨਮ ਮਰਣ ਦੁਖ ਖੋਵਹੁ ॥ ਗੁਰ ਸਤਿਗੁਰ ਸੁਆਮੀ ਭੇਦੁ ਨ ਜਾਣਹੁ ਜਿਤੁ ਮਿਲਿ ਹਰਿ ਭਗਤਿ ਸੁਖਾਂਦੀ ॥ ਕਹੁ ਨਾਨਕ ਪ੍ਰਾਣੀ ਚਉਥੈ ਪਹਰੈ ਸਫਲਿਓ*ੁ ਰੈਣਿ ਭਗਤਾ ਦੀ ॥੪॥੧॥੩॥ {ਪੰਨਾ 77}
“Oh my dear friend as fourth part of life-night comes, a call from Him to depart is served, my friend Guru is above error and seek refuge in him and follow his teachings (what is the teaching?(To be lost in the thoughts of Almighty) Don’t be lazy,( means don’t get lost in other affairs and fail to get time to do simran). Satguru is beyond error (means whatever Satguru says about His Simran is true, don’t doubt it.) Only through simran you will have eternal spiritual experience and be able to experience Waheguru and also it will get you from cycle of coming and going. Do not see any difference between Satguru and Waheguru because taking refuge in Guru’s company you shall be able to fall in love with the creator.
Question: what is the dominating idea in this Shabad?
Answer is Waheguru. What is preached here? Seek refuge in Satguru to do simran.
Why? Guru’s company enables us to fall in love with Waheguru.
Why there is no difference in Satguru and Waheguru( Because Guru has realized Him)
“JIN JATA SO TIS HEE JIHA” Ramkli dakhni Onkar GGS Ji
( means who realizes Him becomes like Him)
Your problem as I see is that you are stuck with “ Satguru sayeen jiha” You guys are more interested in proving that Guru is God, contrary to my position, I stand by Satguru’s bachan that states that in fact Waheguru is beyond birth and death. In that context Satguru declares obviously .In Bharon Mehla 5
ਸਗਲ ਪਰਾਧ ਦੇਹਿ ਲੋਰੋਨੀ ॥ਸੋ ਮੁਖੁ ਜਲਉ ਜਿਤੁ ਕਹਹਿ ਠਾਕੁਰੁ ਜੋਨੀ ॥੩॥ ਜਨਮਿ ਨ ਮਰੈ ਨ ਆਵੈ ਨ ਜਾਇ ॥ ਨਾਨਕ ਕਾ ਪ੍ਰਭੁ ਰਹਿਓ ਸਮਾਇ ॥੪॥੧॥ {ਪੰਨਾ 1136}
This strong declaration is against those who says Waheguru incarnates by cursing them to think that way.
“ਗੁਰ ਸਤਿਗੁਰ ਸੁਆਮੀ ਭੇਦੁ ਨ ਜਾਣਹੁ ਜਿਤੁ ਮਿਲਿ ਹਰਿ ਭਗਤਿ ਸੁਖਾਂਦੀ ॥ Here
Stress is to follow Satguru since as said by Satguru Nanak” ones who totally are lost in His thoughts are become like Him” Onkar GGS JI. Still the principle of Satguru of God’s being beyond incarnation stands intact. Satguru taught us to be logical to be aware of superstitious and fairy tales but this Brahmin mentality is dragging some Sikhs back to the point from where Satguru liberated them.
Another point about immorality of Satguru,( as aad0002 pointed out) there is no doubt he is. Even after over 500 years still Guru is guiding us and will continue for ever. As Satguru inspired, I have fallen for Waheguru. I am unable to pay gratitude what Satguru has done for me, how much I adore and revere Satguru, is beyond words. Do not judge me with your narrow thinking. I have no affiliations to anyone but Guru. Rest is left on ones determination to follow Satguru and respect for what He stood for. His coming was expressed by Bhai Gurdas as “risen sun that dispels mist” but your approach is undoing what Satguru was sent to do and did . Third Nanak very strongly urges us
ਹੁਕਮੁ ਮੰਨਿਹੁ ਗੁਰੂ ਕੇਰਾ ਗਾਵਹੁ ਸਚੀ ਬਾਣੀ ॥ ਕਹੈ ਨਾਨਕੁ ਸੁਣਹੁ ਸੰਤਹੁ ਕਥਿਹੁ ਅਕਥ ਕਹਾਣੀ ॥੯॥ {ਪੰਨਾ 918}
So I am going to follow him, the major dominating principle of Sikhism, to be in love with Him by praising WAHEGURU through Gurbani
Rest I leave to WAHEGURU. When I am full with limitations what right have to judge others. Peace!!