we are convinced: Skilled speakers and writers show confidence in their audience to inspire them (see Romans 15:14).
The author believes his hearers' lives show they truly know God, including their salvation. In the New Testament, salvation mainly refers to Christ’s work on the cross (Hebrews 5:9–10; see also study note on 2:3). Hebrews highlights the completion of salvation at the end of time (9:28).