How do you show your love for a person?  Is it through words, touch, gifts, or service?  All of these come through some sort of giving, some sort of gift: time, energy, attention, etc.  How do you show great love for a person?  The greater the love, the greater the gift.  These gifts can be seen as sacrifices, as something truly costly.  When God wanted to show us His love, He made the greatest sacrifice imaginable.  It cost Him His Son.