What did God do for us after we believed the gospel?
After we believed the gospel, God sealed us with the Holy Spirit of promise. At that moment of salvation we were born again, and the Holy Spirit indwells us, empowers us, and keeps us. This sealing is God's work following faith, plus nothing.
Les explains that after we believed the gospel, God sealed us with the Holy Spirit of promise—'in whom also after that you believed, period, plus nothing.' Paul then explains throughout his epistles that the moment we believe the gospel or are saved, we are born again; the Holy Spirit indwells us, empowers us, and keeps us. Les also points to Ephesians 2, where Paul says God quickened or made alive those who were dead in trespasses and sins, picturing Israel in Egypt and us before salvation, walking according to this world and Satan.
In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise,