Many verses in the Bible are conditional. You only receive the benefits of what God has for you if you commit to an action and remain steadfast in that action. Psalm 91 is a popular chapter for many, but it too is conditional. Plagues can come near your tent (Ps 91:10), and we can be accessible by evil (Ps 91:8) if we do not dwell in the secret place of the Most High (Ps 91:1).
We also speak about wearing a mask due to the coronavirus. Believers should not be wearing one out of fear, but out of obedience to the rules of your city or country (Romans 13:1).
This program covers the following scriptures from the Amplified Classic version (AMPC): Psalm 91:1-10; Luke 10:19.