Guru is the True Companion
Doha Explanation - Guru hī hai saccā sāthī goviṁda rādhe। hari to haiṁ bane bane kā sāthī batā de॥
tasmiṃstajjane bhedābhāvāt - Even though God and Guru are considered one, God does not directly help us. He has existed in our hearts for eternity and is always with us, yet we continue to wander among the 8.4 million species. Because of Maya, we remain ignorant and identify with the body, thereby developing attachment to the material world. So when we compare Hari and Guru, it becomes clear that Guru is our true companion. You can learn philosophical knowledge only from a genuine Guru - what is the soul, what is the Supreme Soul, what is this body, who is God, etc. A genuine Guru is both 'śrotriya' and 'brahmanishtha'. 'Śrotriya' means someone with theoretical mastery who can give you complete and accurate knowledge of the Vedas and scriptures (tattva jñān) and resolve all your doubts. 'Brahmanishtha' means someone practical - one who has attained God.
As you advance in sadhana, obstacles arise that only the Guru can resolve. For example, one sometimes experiences such bliss while meditating on the divine form of God, attributing to it all the divine powers of God, that one faints. The sadhak then wrongly assumes that he has attained God and becomes proud. In reality, that is not God-realization; it is just a 'darśanābhās' (an illusion) - Maya does not leave. Instead, his ego increases, and he dies in the material world. Therefore, at every step, you need guidance from your Guru; you must go to him to resolve all your problems.
Then, after shedding tears in love and longing for God's vision for a long time, when the heart becomes completely pure, and we develop complete detachment from the world (so whether we gain something or lose something, whether someone dies or takes birth, whether we succeed or fail, our mental state remains the same), even then just having a pure heart is not enough. The heart has only become purified, but the vessel is not yet ready; it is still material. Only when the heart becomes divine can we get darshan of the divine Lord. So, Guru bestows his disciple with Swaroop Shakti, God's divine power, thereby making his heart and senses divine. Now, no matter where or in what form God appears, the disciple will be able to recognize Him because his vision has become divine. After so much cleansing, God now comes to reside within.
Therefore, the Guru is regarded as even greater than God. This is why the Guru is the true companion, while God is a companion only to those who have attained him.
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