God says that He has adopted us as His own, "For you did not receive the spirit of bondage again to fear, but you received the Spirit of adoption by whom we cry out 'Abba, Father.'" (Romans 8:15) That word adoption is a compound word in the Greek that means "placing as a son." According to Strong's Exhaustive Concordance (I'm not that smart I just know where to look), "it signifies the place and condition of a son given to one to whom it does not naturally belong."
Do you catch the significance? In essence, God plucks us up--non-son and non-daughter--by His great grace and declares us now His child. It is nothing we have done to deserve the title of "child." He is just gracious and abounding in love.
I would imagine an earthly parent who adopts feels the same. You would not adopt because of the achievements of a little one; you adopt because you want to give your love--freely and abundantly. It is here that we collide with the concept of election.
Volumes have been written about God's "election" of believers. So this short blog entry could never address the many facets. But one thing is sure. Salvation is not dependent on humans. It is a complete work of God from start to finish--a complete gift of love and grace.
If you call yourself His child then revel in the fact that you were chosen by Him to be His own, "you are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light." (1 Peter 2:9, emphasis mine)
Go this day and proclaim His praises. He who called you is faithful.