Revelation 16:14 identifies these as demonic spirits performing signs to gather kings for the final battle.

Revelation 20:10 describes the dragon's final judgment in the lake of fire — the same dragon whose mouth emitted an unclean spirit in 16:13.

Revelation 19:20 records the beast and false prophet cast into the lake of fire — the same figures whose mouths emitted unclean spirits in 16:13.

Revelation 13:11-18 introduces the false prophet who performs signs — the same one whose mouth emits an unclean spirit in 16:13.

Revelation 13:1-7 introduces the beast from the sea with a blasphemous mouth — the same beast that emits an unclean spirit in 16:13.

Revelation 12:9-13 details the dragon's fall and persecution — the same dragon whose mouth emits a deceptive spirit in 16:13.

Revelation 12:4 shows the dragon sweeping stars — the same dragon from whose mouth the unclean spirit comes in 16:13.

Revelation 12:3 introduces the great red dragon — the same dragon whose mouth emits an unclean spirit in 16:13.

1 John 4:1-3 instructs testing spirits to discern false prophets, directly relevant to identifying these unclean spirits.

Exodus 8:2-7 describes the plague of frogs in Egypt, which these frog-like spirits recall as a sign of judgment.

In 2 Thessalonians 2:9-11, the lawless one works deceptive signs and God sends strong delusion, paralleling these demonic signs.

Psalm 105:30 also recalls the plague of frogs in Egypt, another OT parallel to these spirits.

Psalm 78:45 recounts the plague of frogs sent on Egypt, alluded to by the frog-like spirits here.

Zechariah 13:2 prophesies removal of the 'unclean spirit' — the same term used here for the frog-like spirits.

Micah 2:11 describes a man with a false spirit who speaks lies — parallels the lying unclean spirits coming from the false prophet.

1 Timothy 4:1-3 warns of deceitful spirits and doctrines of demons in later times, echoing the unclean spirits here.

2 Peter 2:1-3 warns of false teachers, similar to the deceptive influence of the spirits from the false prophet.

1 Kings 22:22 describes a lying spirit in the mouth of prophets — similar to the unclean spirits from the mouths in 16:13.