Were strengthened (estereounto). Imperfect passive of stereoō, old verb to make firm and solid like the muscles (Act 3:7, Act 3:16), these three the only examples in the N.T.
Increased (eperisseuon). Imperfect active of the old and common verb perisseuō from perissos (overplus). The blessing of God was on the work of Paul, Silas, and Timothy in the form of a continuous revival.