What does 1 Samuel 6:6 mean?

The priests are advising the leaders of the Philistines about how best to send the ark of the Lord (Exodus 25:10–16) back to the Israelites. They hope that doing so will cause the Israelites' God to stop the plagues which have been afflicting them (1 Samuel 5:6–12; 6:2–3). The priests have said plainly the Philistines should send a guilt offering to the Lord and give Him glory (1 Samuel 6:3–5).

Now they tell the leaders not to make the same mistake that the Pharaoh and the Egyptians did when the Lord sent plagues on them. The Pharaoh resisted the Lord and kept hardening his heart, refusing to let the people go (Exodus 7:13, 22; 8:15, 19, 32; 9:7, 12, 34; 10:1–2, 20, 27; 11:10; 14:8). The point the priests of the Philistines are making is that, in the end, the result was the same: The Egyptians let the people go. Why suffer any more than they already have?

It's unclear if the Philistines ever read Moses' version of Exodus, but they clearly knew a version of the story (1 Samuel 4:5–9). More than that, the Philistines learned to fear the God of Israel from the story and intentionally applied what they learned to their own circumstances. The same could not be said of Israel in every season, or even of some modern believers in Jesus. It serves us well to remember that "the fear of the LORD is the beginning of knowledge" (Proverbs 1:7). When we rightly understand who God is—both in His saving grace and in His majestic holiness—we are poised to honor God with our lives (Hebrews 4:11–13; Romans 12:1–2) and to experience true life in Him more richly (John 15:1–11).