Why does the text suggest that worldly relationships are not reliable for spiritual progress, unlike the bond with a Guru?

The text in Chapter 45 argues that worldly relationships are unreliable for spiritual progress because they are rooted in transient interests. It provides specific examples: a mother and father show affection, a son is concerned with the wealth he can claim, and a grieving wife cries for her own status change to widowhood. The passage concludes that "no one is a companion in the spiritual goal" among these relations. This is contrasted with the bond with a Guru, who is equated with the eternal Brahman. The Guru represents a constant, spiritual support system, unlike family ties which are ultimately temporary and often self-interested.