“bread.” “Bread” was a common idiom for food. “Bread” came to be used by metonymy for food in general because bread was the main food in the culture and staple of life. See commentary on Leviticus 26:26.
“table.” We can see from the question and answer that in this context God is using the word “table” for His altar, the altar of sacrifice in the Temple. It is appropriate in this context for God to refer to His altar as a “table” because God is speaking to the priests (Mal. 1:6). The priests ate portions of many of the sacrifices. For example, the priest ate some of the grain offerings (Lev. 6:4-16, 18; 7:9-10), the sin offerings (Lev. 6:26, 29), the guilt offerings (Lev. 7:6), and the fellowship offerings (Lev. 7:28-34). Thus, in a very real sense, the altar of Yahweh was the table of the priests. The altar is also called the “table of Yahweh” in Malachi 1:12.
Furthermore, it was customary in the biblical culture—customary, but not commanded by God—that the two parties who made a covenant would share a meal together. So for God to call His altar a table was also supposed to remind the priests that they had a covenant relationship with God that they were obligated to honor.
There are a few examples of covenant meals in the Bible. That there are not more examples is not surprising, because things that were customary and were “standard operating procedure” were often simply assumed and not specifically mentioned in the Bible. In Genesis 26:28-30 Abimelech made a covenant with Isaac and they shared a meal together. In Genesis 31 Jacob and Laban made a covenant together and shared a meal (Gen. 31:44, 46).
In Exodus 24, the people of Israel made a covenant with God, and that covenant formed the basis of what we now call “the Old Covenant” (or “Old Testament”). The people of Israel sacrificed animals and made the covenant with God (Exod. 24:4-8), then the elders of Israel, the representatives of the people, went up the mountain and saw God (Exod. 24:9-10), and then, upon seeing God, the elders ate a covenant meal (Exod. 24:11). Since the Old Covenant was inaugurated with a blood sacrifice and a shared meal, it is not at all surprising that the Lord Jesus would, at the Last Supper, tell the Apostles to eat of the bread and drink of the wine that represented his body and blood. In that rare case, they ate the covenant meal before the covenant was made because Jesus was the sacrifice, and his shed blood inaugurated the covenant.