Mahabharata 12.135.18

आदौ न कुरुते श्रेयः कुशलोऽस्मीति यः पुमान्स संशयमवाप्नोति यथा संप्रतिपत्तिमान्

ādau na kurute śreyaḥ kuśalo'smīti yaḥ pumānsa saṃśayamavāpnoti yathā saṃpratipattimān

Our plain-language meaning of this verse is waiting for scholar review.