To begin his letter (1 Peter 1:1), Peter describes the recipients first in terms of their relationship to the world, which is the converse of their relationship to God. Peter describes them as “foreigners.” Some translations read “pilgrims” others read “strangers.”
The word describes people who do not hold citizenship in the place in which they reside. Such strangers were seen as subversive to the social order (we tend to have the same attitudes today) and that aptly describes the role of the Christian in society in every age. Without going into great detail, there is much to support the view that these could be Christians who were deported from Rome during one of the several expulsions that occurred during the mid-first century.
Peter writes to encourage them and their encouragement is for us because Christians in every age have values that conflict with the rest of society and culture. Along these lines, Peter uses this designation again in 1 Peter 2:11 where he contrasts the moral values of a Christian with those of the world.
Hebrews 11:13 tells us that we stand in good company because those people of great faith during the y times when God first revealed himself saw themselves in just this same way and “confessed that they were strangers and pilgrims on the earth.” (In the LXX of Gen. 23:4 Abraham describes himself using this very word as he lives among the Hittites.)