The accusation was leveled against Jesus: “This man receives sinners and eats with them.” (Luke 15:1). What the Pharisees meant by this accusation was that Jesus was eating with those who were identified as public sinners—e.g. tax collectors and harlots. To eat with someone was to demonstrate fellowship with that person. How could Jesus display eating-fellowship with such public sinners, thus apparently condoning their sin? Of course—as Scripture explains that all have sinned—every time Jesus eats with people He is eating with sinners.
As one considers the fifteenth chapter of Luke one realizes that an appropriate title for the entire chapter is Repentance. Thus at the close of His first parable Jesus explains, “Just so, I tell you, there will be more joy in heaven over one sinner who repents than over ninety-nine righteous persons who need no repentance.” Similarly in explaining the parable of the lost coin Jesus summarizes: “Just so, I tell you, there is joy before the angels of God over one sinner who repents.” The remainder of the chapter also deals with repentance, as it concludes with the parable of The Prodigal Son.
So when Jesus “ate with sinners” He was not condoning sin, but He who could read the heart was dining with those whom He knew to be penitent sinners. “The sacrifices of God are a broken spirit;
a broken and contrite heart, O God, you will not despise.” (Ps. 51:17).
Now Jesus, the sin offering for mankind, has given to His Church the ultimate meal relating to repentance and forgiveness—the Sacrament of the Altar. Though we correctly magnify the reality that in this meal sinners are eating the very body and blood of Christ given and shed at the cross for the forgiveness of sins, yet the early church—more so than today—magnified the fact that Christ at this Supper was/is also dining with His people.  Jesus had promised not to eat or drink until there would be fulfillment in the kingdom (Luke 22:16-18). Christ’s death, resurrection and the pouring forth of the Spirit at Pentecost, marked the fulfillment in the kingdom. Now whenever God’s kingdom comes through Holy Communion it is apparent from Jesus’ own words that He is drinking the fruit of the vine and eating the “Passover” with His disciples. He is both the Supper’s host and its food.
It may seem strange that while Christians eat and drink of Christ’s body and blood in the Lord’s Supper He is there dining with them. Such mysteries in Holy Communion parallel the very mysteries of the person and work of Jesus. Consider that He is both the Priest and the sacrifice, both the Shepherd and the lamb, and both God and man. In His Blessed Sacrament we miraculously yet truly eat the body and blood of the crucified One, and yet the risen One now dines with His people as surely as He did during those forty days after His resurrection. The Sacrament of the Altar stands as a perpetual reminder of these foundational gospel-mysteries. Truly the Lord Jesus gives to us a sort of double fellowship in the Lord’s Supper. Penitents fellowship with Him as they eat His body and blood given and shed at the cross, and they fellowship with Him as He yet chooses to “receive sinners and eat with them.”
 See e.g. O. Cullmann and F.J. Leenhardt, Essays on the Lord’s Supper (London: Lutterworth Press, 1958).
 Hymns often reflect this. E.g. LSB hymns 620 (v. 2) and 639 (v. 2).