Pistoō (πιστόω, G4104) means to make faithful, to make trustworthy, to assure, to confirm in faith. From pistos (faithful/trustworthy) + the -oō causative suffix. Appears only in 2 Timothy 3:14 — 'continue in what you have learned and have become convinced of (epistōthēs), because you know those from whom you learned it.' It carries the sense of being made firm in conviction, grounded in well-founded trust.
Paul's charge to Timothy in 2 Timothy 3:14 — 'continue in what you have learned and have become convinced of (epistōthēs)' — is a theology of perseverance through knowledge and relationship. Timothy is not merely urged to continue in doctrines but in things he has been personally assured of — through his grandmother Lois and mother Eunice (2 Timothy 1:5), through Paul's own mentorship, and through the Scriptures 'which are able to make you wise for salvation' (2 Timothy 3:15). Pistoō is not cold intellectual assent but confirmed, relational, tested trust. The ground of Timothy's faithfulness is threefold: the character of those who taught him, the content of what he learned, and the Scripture's inherent capacity to produce wisdom. This is the model of generational faith transmission — pistoō in one generation becomes the foundation for the next.