In reference to the passage, you are My friends if you do what I command you. No longer do I call you slaves, for the slave does not know what his master is doing; but I have called you friends, for all things that I have heard from My Father I have made known to you (John 15:14-15), Murray Harris writes.
"It should be observed that although Jesus the Lord call his obedient disciples his friends, they are not thereby authorized to call him their friend. In the Old Testament, Abraham (2 Chr. 20:7; Is. 41:8) is called God's friend.  But this leads James to say, not that 'God was called the friend of Abraham', but that 'he [Abraham] was called the friend of God' (Jas. 2:23). Not, of course, that God or Jesus is unfriendly, but each remains a Lord to be obeyed, not a colleague to be befriended." (Harris, Murray J. Slave of Christ : A New Testament Metaphor for Total Devotion to Christ New Studies in Biblical Theology. Downers Grove, Ill.: InterVarsity Press : Apollos, 2001, 145.)
 Moses, too, is called the friend of God (Exod. 33:11, by implication).