This is because the person is looking for the answer and stopping at Jesus - without continuing to God. Yes, they are one and the same, but bear with me.
We know God does this for us because He LOVES us:
John 3:16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
As well as verse 17 which LCIII supplies.
Through Scripture we learn that God created man and woman in His image, and throughout His creation all things were created to be good. Adam and Eve sinned by not adhering to God's simple rule to not eat of the forbidden fruit, and sin entered the world. This caused a very obvious rift between the Lord and the people He created.
A lot of people have asked me "Why didn't God just do away with sin to begin with?" Well, that is easily answered in our gift of free will. Unlike angels (assumed anyway, depending on the person you ask), mankind has always had a choice as to whether or not we believe and truly worship the Lord. Why would He undo the very will He gave us, if it meant we could no longer choose? He wouldn't. He wants us to choose. This is why we are told of the gifts for believing in Him and His Son, and the end result of not believing. In essence, we are given the foundation and told "Choose wisely.", the sad fact is that many do not.
Jesus was, and is, a model of Love. The Love that God has for all of us despite what we have done, the love that we should have for God and Jesus, and the love we should have for one another.
Nowhere in the Bible that I can recall do we see Jesus using the exact words "I will go save humanity", but we see it stated throughout the New Testament. In the Old Testament we see that God, through the Prophets, wrote about the coming of Christ.