And to know the love of Christ which passeth knowledge, that ye might be filled with all the fulness of God.
Ephesians 3:19 (KJV)
Being filled with all the fullness of God is to know His love in and through Christ Jesus. This surpasses intellectual knowledge and must be known in the heart. When it sinks into our hearts just how much He loves us, our lives cannot help but overflow with His goodness.