CC Ādi 12.9

keha ta’ ācārya ājñāya, keha ta’ svatantra
sva-mata kalpanā kare daiva-paratantra
Word for word: 
keha ta’ — some; ācārya — the spiritual master; ājñāya — upon His order; keha ta’ — some; sva-tantra — independently; sva-mata — their own opinions; kalpanā kare — they concoct; daiva-paratantra — under the spell of māyā.
Translation: 
Some of the disciples strictly accepted the orders of the ācārya, and others deviated, independently concocting their own opinions under the spell of daivī-māyā.
Purport: 

This verse describes the beginning of a schism. When disciples do not stick to the principle of accepting the order of their spiritual master, immediately there are two opinions. Any opinion different from the opinion of the spiritual master is useless. One cannot infiltrate materially concocted ideas into spiritual advancement. That is deviation. There is no scope for adjusting spiritual advancement to material ideas.