In the outward sign of crossing our forehead, lips, and heart, we are asking that the Word of God to pierce our mind, lips, and hearts.
We cross our forehead so that the Word of God may be in our thoughts and purify our minds. We cross our lips so that our speech may be holy and incline us to share the Gospel with others. And we cross our hearts to invite God to strengthen our love for Him and others. All of this is so that we might know, proclaim, and love Jesus Christ all the more.