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.

Amen.


The food of the Jews has some features in common with our spiritual food. They are alike in the fact that each signifies the same thing: for both signify Christ. Thus they are called the same food: “All ate the same spiritual food” (1 Corinthians 10:3). He calls them the same because each is a symbol of spiritual food. But they are different because one [the manna] was only a symbol; while the other [the bread of the Christians] contains that of which it is the symbol, that is Christ himself. Thus we should say that each of these foods can be taken in two ways. First, as a sign only, i.e., so that each is taken as food only, and without understanding what is signified; and taken in this way, they do not take away either physical or spiritual death. Secondly, they may be taken in both ways, i.e., the visible food is taken in such a way that spiritual food is understood and spiritually tasted, in order that it may satisfy spiritually. In this way, those who ate the manna spiritually did not die spiritually. But those who eat the Eucharist spiritually, both live spiritually without sin, and will live physically forever. Thus, our food is greater than their food, because it contains in itself that of which it is the symbol.[10] 

Thomas Aquinas, Commentary on the Gospel of John (Albany, New York: Magi Books, 1980), chapter 6, lectio 6, no. 954.

https://catholic-link.org/spiritual-communion-can/

https://churchlifejournal.nd.edu/articles/the-theology-and-history-of-spiritual-communion/

https://www.stpsu.edu/the-grace-of-spiritual-communion