A sacrament is what brings the life of God into the life of a human.  As important as faith is, God doesn’t merely want us to believe and trust in Him, rather He wants to live inside of us: “It is no longer I who live but Christ who lives in me” (Galatians 2:20).  Through faith, hope and love, together with the sacraments, we as Christians not only trust God, but we live in Him and He in us (John 15:1-11, John 6:56, Romans 6:3-4, 2 Cor. 4:10-12, etc.)