Although the Absolute Truth is one without a second, the sages have described Him in many different ways. Therefore one may not be able to acquire very firm or complete knowledge from one spiritual master.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
न ह्येकस्माद्गुरोर्ज्ञानं सुस्थिरं स्यात्सुपुष्कलम् । ब्रह्मैतदद्वितीयं वै गीयते बहुधर्षिभिः
na hyekasmādgurorjñānaṃ susthiraṃ syātsupuṣkalam | brahmaitadadvitīyaṃ vai gīyate bahudharṣibhiḥ
SB 11.9.31