Bhai Gurdas Ji, in the following verse, explains why Sikhs should not mix their faith with other religions.
ਦੋਇ ਦਰਪਨ ਦੇਖੈ ਏਕ ਮੈ ਅਨੇਕ ਰੂਪ ਦੋਇ ਨਾਵ ਪਾਵ ਧਰੈ ਪਹੁਚੈ ਨ ਪਾਰਿ ਹੈ ।
Just as looking into two or more mirrors placed side by side show more than one image; and placing feet in two boats does not enable one to sail across the river.
ਦੋਇ ਦਿਸਾ ਗਹੇ ਗਹਾਏ ਸੈ ਹਾਥ ਪਾਉ ਟੂਟੇ ਦੁਰਾਹੇ ਦੁਚਿਤ ਹੋਇ ਧੂਲ ਪਗੁ ਧਾਰਿ ਹੈ ।
Just as the arms or legs are put to risk of breaking when pulled from both sides at the same time; one often errs in selection of the right path at the cross-road.
ਦੋਇ ਭੂਪ ਤਾ ਕੋ ਗਾਉ ਪਰਜਾ ਨ ਸੁਖੀ ਹੋਤ ਦੋਇ ਪੁਰਖਨ ਕੀ ਨ ਕੁਲਾਬਧੂ ਨਾਰਿ ਹੈ ।
Just as a city if ruled by two kings cannot provide peace and comfort to the subjects, nor can a woman wedded to two men can be sincere and loyal or faithful to either family.
ਗੁਰਸਿਖ ਹੋਇ ਆਨ ਦੇਵ ਸੇਵ ਟੇਵ ਗਹੈ ਸਹੈ ਜਮ ਡੰਡ ਧ੍ਰਿਗ ਜੀਵਨੁ ਸੰਸਾਰ ਹੈ ॥੪੬੭॥
Similarly, if a devout Sikh of Guru worships other gods and goddesses to assuage his addiction, what to speak of his liberation, he even bears the punishment of the angels of death. His life is condemned by the world. (467)
– Bhai Gurdaas Ji
In short, Bhai Gurdas Ji is saying that a true Sikh should stay loyal to their Guru and not mix their beliefs with other religions. Following two paths only leads to confusion, suffering, and a lack of spiritual fulfillment.
ਜਾਗਤ ਜੋਤਿ ਜਪੈ ਨਿਸ ਬਾਸੁਰ ਏਕੁ ਬਿਨਾ ਮਨਿ ਨੈਕ ਨ ਆਨੈ ॥
He is the true Khalsa (Sikh), who remembers the ever-awakened Light throughout night and day and does not bring anyone else in the mind
ਪੂਰਨ ਪ੍ਰੇਮ ਪ੍ਰਤੀਤ ਸਜੈ ਬ੍ਰਤ ਗੋਰ ਮੜ੍ਹੀ ਮਠ ਭੂਲ ਨ ਮਾਨੈ ॥
He practices his vow with whole heated affection and does not believe in even by oversight, the graves, Hindu monuments and monasteries.
– Guru Gobind Singh Ji
These verses by Guru Sahib describe the true Khalsa as someone who constantly remembers and meditates on the ever-awakened Light, referring to Waheguru, both day and night. Such a person does not let their mind focus on anything or anyone else besides the One God. This highlights the importance of single-minded devotion in Sikhi, where the devotee remains connected to the Divine at all times, not allowing any other thoughts or deities to take the place of Waheguru.
A true Khalsa practices their faith with complete love and sincerity. They do not believe in or practice rituals related to graves, Hindu monuments, or monasteries. Guru Gobind Singh Ji is instructing Sikhs to stay away from superstitions, rituals, and practices that distract from the path of true devotion. The Khalsa’s faith is pure and untainted by such external rituals.