Chapter 7 · Knowledge and Realisation · Krishna said
Bhagavad Gita 7.21 — God steadies all faith
यो यो यां यां तनुं भक्तः श्रद्धयार्चितुमिच्छति। तस्य तस्याचलां श्रद्धां तामेव विदधाम्यहम् ॥
yo yo yāṃ yāṃ tanuṃ bhaktaḥ śraddhayārcitumicchati | tasya tasyācalāṃ śraddhāṃ tāmeva vidadhāmyaham ||
Meaning
Whatever form a devotee wishes to worship with faith, I make that devotee's faith in that very form firm.