Joel 2:11

¹¹ And Jehovah hath given forth His voice before His force, For very great [is] His camp, For mighty [is] the doer of His word, For great [is] the day of Jehovah -- very fearful, And who doth bear it?

Wall, rampart, gates, and bars

In Lamentations 2:8-9, the 'wall,' 'rampart,' 'gates,' and 'bars' signify doctrines.