The Eucharist, also called Holy Communion, Sacrament of the Table, the Blessed Sacrament, or The Lord's Supper, is considered to be a re-enactment of the Last Supper, the final meal that Jesus shared with his disciples before his arrest and crucifixion, during which he gave them bread, saying. "This is my body", and wine, saying, "This is my blood".
The Lord Jesus instituted the Holy Eucharist on Holy Thursday, in the upper room of Zion, shortly before his arrest and trial. After he celebrated the Rite of Passover of the Jews, he rose and washed the feet of his disciples, as a sign of repentance and preparation, then sat down and instituted the Sacrament of Holy Communion.
Receiving Holy Communion brings us graces that affect us both spiritually and physically. Spiritually, our souls become more united to Christ, both through the graces we receive and through the change in our actions that those graces effect. Frequent Communion increases our love for God and for our neighbor, which expresses itself in action, which makes us more like Christ.