you can begin reading sections 1066-1212 on the Liturgy and Paschal mystery, and 1322-1421 on the Eucharist, available on the US bishop’s website, ussccb.org
Here’s a quote “the source and summit of the Christian life” (Lumen gentium, no. 11; cf. Catechism of the Catholic Church, no. 1324). Since the Christian life is essentially a spiritual life, we might say as well that the Eucharist is the “source and summit of Christian spirituality” too.
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