In plain words
The faith of every being conforms to its mind (sattva), Bharata. This person is made up chiefly of faith; whatever one’s faith is, that indeed one is.
Word for word
Conforming to [the] sattva [is] the śraddhā of everyone, O Bhārata; this person [is] made of śraddhā; who [has] whatever śraddhā, just that [is] he.
सत्त्वानुरूपा सर्वस्य श्रद्धा भवति भारतश्रद्धामयोऽयं पुरुषो यो यच्छ्रद्धः स एव सः
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam
सा इयं त्रिविधा भवति —
सत्त्वानुरूपा विशिष्टसंस्कारोपेतान्तःकरणानुरूपा सर्वस्य प्राणिजातस्य श्रद्धा भवति भारत । यदि एवं ततः किं स्यादिति, उच्यते — श्रद्धामयः अयं श्रद्धाप्रायः पुरुषः संसारी जीवः । कथम् ? यः यच्छ्रद्धः या श्रद्धा यस्य जीवस्य सः यच्छ्रद्धः स एव तच्छ्रद्धानुरूप एव सः जीवः ॥ ३ ॥
In plain words
And this same one comes in three forms —
Faith takes shape according to sattva -- that is, according to the inner mind, as it has been shaped by its own particular past impressions -- and this holds for every living being, Arjuna. So if that is true, what follows from it? Here is the answer: this person -- this transmigrating soul -- is made of faith, mostly faith. How so? Whatever faith a soul carries, that is exactly who he is: he himself, precisely, is shaped exactly by that faith -- nothing more, nothing less.
Close to the Sanskrit
That this becomes threefold —
Conforming to sattva -- conforming to the inner instrument as furnished with particular impressions -- faith is thus, of every class of living being, O Bharata. If this is so, then what follows from it? It is said: 'this person is made of faith,' i.e. mostly faith -- the transmigrating individual soul. How [is this so]? 'Whoever has whatever faith' -- whatever faith belongs to a jiva, he has that faith -- he himself, precisely, conforming to that faith, precisely, is that jiva.