The highest proof of God's love is that He sent His Son to die for all our sins, and to grant us His life through His Son:
"A man that hath friends must shew himself friendly: and there is a friend that sticketh closer than a brother."(Job 18: 24)
This verse is about Jesus!
"Greater love hath no man than this, that a man lay down his life for his friends." (John 15: 13)
Yet we are more than just friends with God, even though Jesus did extend this new standing to us:
"Henceforth I call you not servants; for the servant knoweth not what his lord doeth: but I have called you friends; for all things that I have heard of my Father I have made known unto you." (John 15: 15)
Yet God's love through His Beloved Son is much greater than any ordinary man's love:
"6For when we were yet without strength, in due time Christ died for the ungodly. 7For scarcely for a righteous man will one die: yet peradventure for a good man some would even dare to die. 8But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us. 9Much more then, being now justified by his blood, we shall be saved from wrath through him." (Romans 5: 6-9)
Jesus died for us when we were not even His friends, but His enemies, because of sin, because of Adam:
"The vine is dried up, and the fig tree languisheth; the pomegranate tree, the palm tree also, and the apple tree, even all the trees of the field, are withered: because joy is withered away from the sons of men." (Joel 1: 12)
"12Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned." (Romans 5: 12)
We bring nothing to our salvation. He brought everything, and all we can respond with is: "Thank You!"
"21And you, that were sometime alienated and enemies in your mind by wicked works, yet now hath he reconciled 22In the body of his flesh through death, to present you holy and unblameable and unreproveable in his sight: 23If ye continue in the faith grounded and settled, and be not moved away from the hope of the gospel, which ye have heard, and which was preached to every creature which is under heaven; whereof I Paul am made a minister;" (Colossians 1: 21-23)
This passage could not be clearer, or more manifest about this truth: He has given us proof of His love for us, and we had nothing to do with it.
We do not become friends of God because of what we did, but because of what He did.
Yet we are more than friends. We are made brothers with Christ:
"And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence." (Colossians 1: 18)
"For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren." (Romans 8: 29)
Yet notice that the verse in Proverbs speaks about One who is close than a brother. . .
"That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me." (John 17: 21)
And of course:
"Herein is our love made perfect, that we may have boldness in the day of judgment: because as he is, so are we in this world." (1 John 4:1 7)