yat-pāda-pallava-yugaṁ vinidhāya kumbha-
dvandve praṇāma-samaye sa gaṇādhirājaḥ
vighnān vihantum alam asya jagat-trayasya
govindam ādi-puruṣaṁ tam ahaṁ bhajāmi
"I worship the primeval Lord, Govinda. Gaṇeśa always holds His lotus feet upon the pair of tumuli protruding from his elephant head in order to obtain power for his function of destroying all obstacles on the path of progress in the three worlds." (Brahma-saṁhitā 5.50)
Śrī Caitanya-caritāmṛta Ādi 7.157
Concerning Ganesa worship, it is not actually necessary for us. But, if someone has a sentiment for getting the blessings of Ganesa in order to get large amounts of money for Krishna's service, then it is alright, but anyone who takes up this kind of worship must send me at least 100,000 dollars monthly—not less. If he cannot send this amount, then he cannot do Ganesa worship.
Letter to: Bhakta dasa — Honolulu 1 February, 1975
When the mode of goodness is mixed with the mode of ignorance, he worships Gaṇapati, or Gaṇeśa.
Śrī Caitanya-caritāmṛta Madhya 24.330