"Now as they were eating, Jesus took bread, and blessed, and broke it, and gave it to the disciples and said, 'Take, eat; this is my body.'
And he took a cup, and when he had given thanks he gave it to them, saying, 'Drink of it, all of you; for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.'" (Matthew 26:26-28)
The mode of Christ's presence under the Eucharistic species is unique.
It raises the Eucharist above all the sacraments as "the perfection of the spiritual life and the end to which all sacraments tend."
In the most blessed sacrament of the Eucharist "the body and blood, together with the soul and divinity, of our Lord Jesus Christ and, therefore, the whole Christ is truly, really, and substantially contained."
"This presence is called 'real' - by which is not intended to exclude the other types of presence as if they could not be 'real' too, but because it is presence in the fullest sense: that is to say, it is a substantial presence by which Christ, God and man, makes himself wholly and entirely present."
- The Catechism of the Catholic Church: paragraph 1374