Why do we receive while kneeling?
The posture of kneeling is a sign of prayer, reverence and penitence. In Holy Scripture, Our Lord even knelt while praying along with many holy men. As St. Paul writes, because of Christ's humility to become man and to suffer death on a cross, He has a "name which is above every name, that at the name of Jesus every knee should bow, in heaven and on earth and under the earth" (Phil 2:5-10). So, during Mass, the laity spend much of the Mass kneeling in prayer and it is the normal posture for receiving Communion. On a practical level, it allows the communicant to be more recollected as he receives and avoids the temptation to move suddenly which may make distributing Communion harder for the priest. As an extension of this practice, whenever entering Church or before going into our pews, the faithful should genuflect (bending their right knee to the floor) to honor Jesus truly present in the Tabernacle.