Psalms 121:6

The sun will not harm you by day, or the moon by night. ¹ 

Ps 91:5-10; Isa 49:10; Re 7:16

¹ sn One hardly thinks of the moon’s rays as being physically harmful, like those of the sun. The reference to the moon may simply lend poetic balance to the verse, but it is likely that the verse reflects an ancient, primitive belief that the moon could have an adverse effect on the mind (note the English expression “moonstruck,” which reflects such a belief). Another possibility is that the sun and moon stand by metonymy for harmful forces characteristic of the day and night, respectively.