Psalms 105:31 Commentary: God Speaks, Plagues Obey

The plagues of lice and flies are the third and fourth plagues in Exodus (Exodus 8:16, 32). Lice (or gnats) come from dust struck by Aaron's rod; the magicians could not replicate this and declared it 'the finger of God.' Swarms of flies follow, arising from the Nile and filling Pharaoh's houses and all Egypt. The Hebrew word for 'flies' (עָרֹב, a·rov) has a range of meanings. The root suggests 'mixture' or 'confused mass,' so some translations render it 'divers sorts of flies' (KJV) or 'dog-flies' (Darby). Jewish commentator Kimchi, as cited by Gill, understood it as 'evil beasts.' The Septuagint and Vulgate favor a particular biting fly. The term for 'lice' (כִּנִּים, ki·nim) is also disputed, Josephus and many Jewish sources take it as lice, while the LXX and Vulgate translate it as 'mosquitoes' or 'gnats.' The psalmist's phrase 'in all their borders' (or 'coasts') emphasizes the comprehensive scope: no corner of Egypt was untouched.

Psalm 105 has strong links to Exodus and to 1 Chronicles 16, where a similar song was used when the ark was brought to Jerusalem. The psalmist selects these two plagues out of the ten, perhaps to highlight how God used the smallest and most annoying creatures to humble the most powerful empire. The Hebrew verb sequence, אָמַר (he spoke) followed by וַיָּבֹא (and it came), echoes the creation language of Genesis 1, where God speaks and things come into being. This literary pattern underscores the point: as at creation, God's word carries the power to command nature itself.

The supplied sources note no significant textual variants for Psalm 105:31. Translations differ in rendering the Hebrew nouns עָרֹב and כִּנִּים, reflecting lexical uncertainty rather than manuscript variation. No textual issues are identified by the consulted commentaries.

Jewish interpreters, including Josephus, generally identified the plague of כִּנִּים as lice, while the Septuagint and Vulgate translated it as mosquitoes or gnats, a reading that influenced later Christian exegesis (as noted by Ellicott). The psalm's use in synagogue and early Christian worship, seen in its connection to 1 Chronicles 16, made this verse part of regular liturgical remembrance of the exodus. Reformation commentators such as Calvin and Henry focused on the theological point: God's word alone suffices to bring judgment and deliverance. In modern study, the verse is often cited to illustrate the power of God's creative word (Psalm 33:9) and his use of the weak to humble the strong.

Three-point outline

1. God speaks, and it happens. The verse shows the sheer power of God's word. No incantations or rituals, just ‘he spoke.’ The Hebrew perfect verb אָמַר points to a decisive act. This reinforces that God's command is the only cause needed.
2. Small things humble the proud. Flies and lice, not armies or plagues of blood, break Egypt's resistance. The magicians could not duplicate the lice, admitting a power greater than theirs (Exodus 8:18, 19). God often uses what is weak to shame the strong.
3. No border contains God's judgment. The phrase ‘in all their borders’ stresses that Egypt's entire territory, from royal palace to peasant hut, fell under the plague. God's reach extends to every corner.

Five-point outline

1. The authority of God's word, Psalm 105:31 emphasizes creation-by-speech (compare Psalm 33:9).
2. The progression of judgment, The lice (third plague) broke the magicians' power; the flies (fourth) struck at daily life.
3. Humility through small things, God does not need spectacular power; gnats are enough.
4. Comprehensive scope, ‘All their borders’ means no one escaped the demonstration.
5. Part of a larger story, The plagues are not isolated; they led to Israel's exodus, which itself points to God’s faithfulness to his covenant.

Illustration hooks

• A single mosquito in a quiet room: how the tiniest annoyance can disrupt comfort and command attention. God used such small creatures to disturb an entire kingdom.
• A spoken command that changes everything: think of a leader giving one order that transforms a situation. God's word carries infinitely more authority, it creates what it commands.
• No safe zone: a pest infestation in a modern home does not spare any room; similarly, God's judgment reached everywhere in Egypt, leaving no hiding place.

Questions your congregation is asking

• Why does God use such small, irritating creatures instead of dramatic displays of power?
• How does this verse show God's control over nature today?
• If God could judge Egypt with flies and lice, what does that say about his ability to judge injustice now?

Psalm 105:31 is a brief snapshot in a long poem recounting God's mighty acts for Israel. This verse reminds us that God's word is active and powerful, and that the smallest of his creatures can carry out his purposes. As you discuss, keep in mind that the psalmist is not just retelling history, he is calling God's people to praise in response to God's faithful power.

Discussion questions

1. Read Exodus 8:16, 24. What do you notice about the details of the third and fourth plagues that the psalmist chose to include or omit?
2. The psalmist writes, ‘He spoke, and there came…’ How does this wording connect to Genesis 1 and the account of creation?
3. Why do you think the magicians could not replicate the plague of lice, but could produce frogs and turn water to blood (Exodus 8:18, 19)?
4. How does the phrase ‘in all their borders’ (or ‘coasts’) emphasize the total reach of God's judgment?
5. What might it have been like for an ordinary Egyptian family during these plagues? How would they have perceived the God of Israel?
6. This psalm was likely used in worship (1 Chronicles 16). How does recounting past judgments lead to praise?
7. Where in your own life do you need to remember that God can use small, unexpected things to change situations?