What does Psalm 91:12 mean?
The prior verse indicated God would use His angels to protect those who believe in Him (Psalm 91:11). The terminology of this psalm is beautiful, and dramatic. However, it is not intended to be used as an obligation for God to keep anyone safe from harm, all the time, and in all circumstances. Satan tempted Jesus with these words, and that error (Matthew 4:5–6). Christ refuted that twisting of God's Word (Matthew 4:7; Deuteronomy 6:16).Those who stay near to God (Psalm 91:1–2) and His wisdom (Proverbs 1:7) are far less likely to suffer the consequences of sin and evil (Proverbs 9:11–12). As other psalms indicate, hardship and struggle are still part of life (Psalm 3:1–2; 73:2–3). Difficulty in this life is to be expected (John 16:33). However, nothing can happen outside of God's will and His plan (Romans 8:28).
Psalm 91:5–13 points out that those who trust in the Lord have nothing to fear because the Lord watches over them. This continues the theme introduced in the prior passage. This segment is notable in that it was cited by the Devil when he tempted Jesus in the wilderness (Matthew 4:5–6). Jesus responded to Satan's attempt at twisting Scripture with additional Scripture and a better perspective (Matthew 4:7). Trust in God's sovereignty and goodness does not mean an absolute expectation of safety.
The psalmist expresses his trust that God is a source of safety. He uses various dangers as symbols of the terrors which God's people do not need to fear. When God has resolved to protect someone, nothing can overcome that safety. Jesus refuted inappropriate use of this promise when being tempted by Satan (Matthew 4:5–7). Those who love God, and honor Him, can count on His provision and protection, and know that nothing happens without His approval.