The nations are summoned around Zion to hear God speak (verses 1–2). We expect God will be judging the heathens, but instead we are startled to find that he is assembling the nations to witness as he brings testimony against his own people (verses 5–7). God’s judgment “begin[s] with God’s household” (1 Peter 4:17). While our salvation in Christ assures us that our sins can’t bring us into ultimate condemnation (Romans 8:1), it also means that with our greater spiritual resources God holds us more responsible for living as he prescribes. To whom much is given much will be required (Luke 12:48). Christians are more loved and pardoned—and yet called to a stricter account at the same time.
God rebukes his people for two things. The first is external religiosity without inward heart change. Verses 8–13 show people who think their worship offerings are somehow doing God a favor. This is moralism, the idea that with our ethical life and religious observance we can put God in our debt, so that he owes us things. On the contrary, grateful joy for our undeserved, free salvation should be motivating all we do (verses 14–15). Examine your heart. Do you feel God owes you a better life? Do you obey him because you feel you have to in order to get what you want, or out of loving wonder for what he has done?