Saint Thomas Aquinas defined “spiritual communion” as “an ardent desire to receive Jesus in the Holy Sacrament and a loving embrace as though we had already received Him. Saint Teresa of Avila wrote: “When you cannot receive Communion and cannot attend Mass, you can make a spiritual communion, which is a most beneficial practice; by it the love of God will be greatly impressed on you.”
An Act of Spiritual Communion:
My Jesus, I believe that You are present in the Most Holy Sacrament. I love You above all things, and I desire to receive You into my soul. Since I cannot at this moment receive You sacramentally, come at least spiritually into my heart. I embrace You as if You were already there and unite myself wholly to You. Never permit me to be separated from You.