In Hebrew culture, the expression 'flesh and blood' denotes the whole human being in his/her mortal condition. Jesus wants us to receive him in his entirety - his humble humanity so that he can communicate to us his divinity.
The risen Christ shares his life, transformed by the Spirit, with those who eat his flesh and drink his blood. 'It is the Spirit that gives life.' (v. 63). This is the mystery as well as the grace of the Sacrament of the Holy Eucharist.
'Sacrament', as the Church defines it, is something material that symbolizes and brings about a spiritual reality. In the Eucharist, we really receive the body and blood of Christ through the two species, bread and wine. And the risen Christ becomes for us the food of eternal life.
Like the Israelites and the Jews of Jesus' time, we may not be easily convinced that receiving the Eucharist, the living bread that is the body of Christ, can actively change us. But Jesus said, 'Whoever eats me will have life through me' (v. 37).
Lord Jesus Christ, help me to participate fully in the Eucharist, to experience Your gift of growth and transformation in me.