This verse sets forth the antithesis between those who do good (the righteous) and those who do evil, a theme which is already mentioned more than once in the letter (verses 9 and 11 above; also 2.14-16, 20). The Lord in its original context refers to God, or to Yahweh, but here, as in 1 Peter 1.25 and 2.3, probably the Lord Jesus Christ is intended. However, it is perhaps best not to make this information explicit in the translation, to do justice to the original context of the quotation. The Lord watches is literally “the eyes of the Lord are upon,” a biblical idiom which gives the idea of God “guarding,” “watching,” “directing,” “caring for,” “looking after” (Biblia Dios Habla Hoy), “paying attention to” (Die Bibel im heutigen Deutsch), “looking with favor” (Barclay). For righteous, see 2.24, where the nominal form “righteousness” is used. Listens to their prayers is literally “his ears unto their prayers,” a biblical idiom which means that God hears and answers their prayers (compare Barclay “is always ready to hear their prayer”).
In contrast to this attitude towards the righteous (but), the Lord opposes those who do evil. Literally “the face of the Lord is upon those who do evil,” once again a biblical idiom. “The face of the Lord” is an anthropomorphic way of speaking of the Lord himself, or his presence, either positively or negatively. Here the negative force is meant: the Lord comes to oppose evil ones. Those who do evil in its original context refers to the wicked; here it is not simply a description of non-Christians who do bad against Christians, but also a warning to Christians against indulging in wickedness.
God’s opposition to those who do evil may be expressed in very general terms by “but he is against those who do evil.” Sometimes this opposition may be expressed as “but God works against those who do evil.”
It is perhaps important to note here that Psalm 34.16 ends with a concluding statement that God will “cut off the remembrance of them (the evil ones) from the face of the earth” (Revised Standard Version). Peter has not included this conclusion, probably because of his theme (later developed in 3.18-20 and 4.6) that God does not reject evil people forever; on the contrary, he has made a way for them to enjoy the benefits of right relationship with God.
Quoted with permission from Arichea, Daniel C. and Nida, Eugene A. A Handbook on The First Letter from Peter. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .