When a devoted Sikh meets True Guru, his vision gets absorbed in the sight/glimpse of the Guru. And then his soul recognises everyone as if He resides in all; like the sky/space resides equally in all the water pitchers.
The union of a True Guru and a Sikh blesses the Sikh with the capability of remaining engrossed in the words/precepts of the Guru. As a musician gets totally engrossed in the tune that he is playing, so is the case of a Sikh's absorption in his Guru.
With the concentration of mind and Guru's words in a Guru devotee, he realises all the happenings of the three worlds within his body.
By the help of divine knowledge, the soul of a Guru devotee becomes harmonious with One Lord who is present in every bit of His creation. This union is like the merging of a river water in the ocean. (63)