The biblical record indicates several instances where human beings see and interact with angels (i.e.
Gen 19:1-3; Dan 6:22; Luke 1:11-20; 26-38; Acts 8:26; 10:3-6; 12:6-11; 27:23-24).
However, human beings may not recognize an angel. The writer of Hebrews encourages Believers to continue
showing hospitality to strangers, because they may be entertaining angels without knowing it (Heb 13:2).