The background of a covenant meal is deeply rooted in the culture of the ancient Near East and serves as a vital thread throughout the biblical narrative, symbolizing peace, fellowship, and the formal ratification of a binding agreement. In ancient times, sharing food was a profound act; only parties who were at peace would sit down to dine together. Source:BibleHub

Luke 15:2 And the Pharisees and the scribes grumbled, saying, “This man receives sinners and eats with them.”

The Pharisees and scribes would never allow sinners into their homes, nor would they enter the homes of sinners. They believed it was a sign of an agreement between themselves and sinners thereby making peace. They saw themselves as above all that.

Isaiah 52:13  Behold, my servant shall act wisely; he shall be high and lifted up, and shall be exalted.

When one adopts an attitude that they are “the servant” of God they exalt themselves. They ignore everything that does not fit that narrative.

Isaiah 57:15 For thus says the One who is high and lifted up, who inhabits eternity, whose name is Holy: “I dwell in the high and holy place, and also with him who is of a contrite and lowly spirit, to revive the spirit of the lowly, and to revive the heart of the contrite.”

Romans 12:16, Philippians 2:3, Romans 12:3, 1 Corinthians 4:7 – Scripture instructs believers to avoid haughtiness, selfish ambition, and overestimating themselves, reminding us not to boast about what we have received. Source: Crosswalk

Those instructions come from a covenant relationship with our Lord. The Pharisees and scribes did not partake of a covenant meal with Jesus because sinners were at His table.

“This is my body, take, eat.” Nope, wasn’t gonna happen with those two groups.