Easton's Bible Dictionary
The materials of which gates were made were,
At the gates of cities courts of justice were frequently held, and hence "judges of the gate" are spoken of (Deuteronomy 16:18; 17:8; 21:19; 25:6,7 , etc.). At the gates prophets also frequently delivered their messages (Proverbs 1:21; 8:3; Isaiah 29:21; Jeremiah 17:19,20; 26:10 ). Criminals were punished without the gates (1 Kings 21:13; Acts 7:59 ). By the "gates of righteousness" we are probably to understand those of the temple (Psalm 118:19 ). "The gates of hell" (RSV, "gates of Hades") Matthew 16:18 , are generally interpreted as meaning the power of Satan, but probably they may mean the power of death, denoting that the Church of Christ shall never die.
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain.
Easton, Matthew George. Entry for 'Gate'. Easton's Bible Dictionary. https://www.studylight.org/dictionaries/eng/ebd/g/gate.html. 1897.