Arjuna asks what happens when a person has Shraddha (trust in the Shastra) but it is not able to follow the stipulations of the Shastra. Lord Krishna responds that a person is what his Shraddha is. He gives a nuanced description of the degrees of Shaddha (derived from Sattva, Tajas, and Tamas). He then talks of how to develop a more Sattvika disposition, specifying food, worship, austerity, and charity and the intentions behind them. By making these choices we develop Sraddha
An Audio Course on Vedanta Texts- Bhagavad Gita: Bhagavad Gita (Chapter 17) by Swami Tattvavidananda Saraswati.