How can a holy, perfect God ever call a flawed human being His friend? God is so far above everyone and everything! Yet three times in the Scripture, Abraham is called God's friend. In 2 Chronicles 20:7, he's referred to as "Abraham Your friend forever." James 2:23 tells us, "And he was called the friend of God." But my favorite one is Isaiah 41:8, where God says it Himself: "But you, Israel, are My servant, Jacob whom I have chosen, the descendants of Abraham My friend."
The thought of being God's friend boggles our mind, but it delights our heart. We smile when we hear the words of Jesus, "I no longer call you servants, I call you my friends" (see John 15:15).
Looking at the example of Abraham, there are a few things you need to be God's friend. First, you need to be spontaneous. In Genesis 18, God just appeared to Abraham. You can't predict God's intervention in your life. You just have to be prepared to respond to Him.
Second, you need humility. When the Lord appeared to him, Abraham's first action was to bow (v. 2). Worship is the proper response to having a friendship with God. Worship, if it's done right, is one of the most selfless acts because all of the focus is off you and onto God. It takes two things: seeing God as He really is, and seeing yourself as you really are. If you see those things, worship will happen; it will be very natural.
And then there's ministry. If you want to be a friend of God you will be involved in serving (vv. 3-8). Our ministry is to the Lord first, and then to others. Even if you're serving without any fanfare, the fact that you're serving Him makes all the difference.
And finally, there's conformity. What I mean is, when God is your Friend, you will trust Him and you will conform to His will. You'll be an obedient person. Jesus said, "You are my friends if you do whatever I command you" (John 15:14). We show our friendship with Christ by obeying Him in all things. You can't pick and choose what areas of life you're going to obey Him and then call God your Friend.
If you have God as your Friend, you don't need much else! I'd rather have God as my friend and the whole world as my enemy, than to have all the friends in the world and God as my enemy.
So give Him your trust, your loyalty, and your obedience. He is worthy of it all!