Brihad Bhagavatamrta
Part 1 Chapter 7 Text 128

icchet punas tadrsam eva bhavam
klistam kathancit tad-abhavatah syat
yesam na bhatiti mate ‘pi tesam
gadhopakari smrti-dah priyanam

TRANSLATION
One may want to feel that separation again, and may indeed feel distressed if one cannot. Thus a person who can remind one of a beloved not present is considered the most sincere and helpful friend.