What does Luke 4:8 mean?

Christ responds to Satan's offer of earthly power in exchange for worship (Luke 4:5–7). As in the other cases, Jesus quotes Scripture and resists the temptation. Instead of taking earthly authority now, avoiding the suffering of the cross, Jesus chooses to obey God and wait for all things to be given in their due time (Philippians 2:8).

Jesus' citation here is from Deuteronomy 6:13. In that book, Moses repeats much of Israel's history. He recounts the commands and lessons given to them by God. Among those are commands to remember and to trust. In the passage to which Jesus refers, Moses reminds Israel that it was God—and God alone—who rescued them from slavery in Egypt. To ignore that salvation and pursue other gods would be a heinous sin.

Satan's temptation of Jesus, in this case, is to do exactly that: to "forget" God and serve some other master. The bait of this temptation is the allure of an easier, "better" life. Jesus knows that this offer is not only a lie, but also pointless. He's been promised all those things, anyway, so long as He follows the Father's will. In the same way, Christians should resist the lies of "prosperity preachers" and earthly sins; God has promised us reward and happiness far beyond that in heaven (1 Corinthians 9:24; Colossians 3:23–24).