Abraham was called "friend" because his TRUSTING faith (faith for faith, you only trust whom you LOVE,...or should) was "reckoned" (seen as) LOVE (Abraham didn't have to MAKE AN EFFORT to SHOW/EXPRESS, his love was OBVIOUS).
God put many examples for us to notice/choose from in scripture, but few have ever noticed because of a preoccupation with COMMANDS and OBEDIENCE (those are important for the REBELLIOUS).