Let’s read about the “breaking of bread” (which is usually referred to as “The Lord’s Supper”) in Luke 22:19-20, “And He (the Lord Jesus) took bread, gave thanks and broke it, and gave it to them, saying, ‘This is My body which is given for you; do this in remembrance of Me’. Likewise He also took the cup after supper, saying, ‘This cup is the new covenant in My blood, which is shed for you’” (NKJV).

The Lord Jesus had just finished celebrating the Passover with His disciples and then He immediately instituted the Lord’s Supper, using the bread and the cup of wine that had been used in the Passover meal. He knew He was on the way to the cross to take the sinner’s place in death and judgment and in this sacred “Memorial Feast” the Lord would be giving believers the opportunity to sit down and to REMEMBER HIM IN HIS DEATH. The “bread” would remind us of His body that He willingly laid down at Calvary as an offering for sin. On that cruel cross He received the judgment that we deserved and the apostle Peter reminds us in 1st Peter 2:24 that the Lord Jesus “bore our sins in His own body on the tree.” The “cup” would remind us of His blood which was shed for the remission of our sins. Because the Lord said, “This do in remembrance of Me,” it is quite proper to call the breaking of bread a “Remembrance Meeting.” The emblems used are simply bread and wine, yet they serve to illustrate the Lord’s body and blood and thus they “bring to our minds and hearts” the tremendous cost to our Savior to redeem us from the penalty of our sins.

You mentioned “breaking bread on a Sunday,” but it is precious to see that initially believers BROKE BREAD DAILY. Acts 2:46 says, “So continuing DAILY with one accord in the temple, and BREAKING BREAD FROM HOUSE TO HOUSE.” I believe their hearts were so filled with love and praise for the Lord Jesus that they were led to sit down to this blessed supper each and every day. No doubt actual images of their Savior came to mind, for most or all of them were no doubt present during the crucifixion. This would have served to humble them as they were REMINDED of what the Savior was willing to endure in order to procure their salvation. Of course, there were also “three hours of darkness” where they couldn’t see the Lord Jesus and eventually they learned that it was during those three hours that their sins were actually laid on Christ followed by God’s wrath being poured out because of those sins (see Isaiah 53:5-6, 10; 2nd Corinthians 5:1; 1st Peter 2:24; 3:18).

In time, the breaking of bread was celebrated on Sunday, the first day of the week. This is brought out in Acts 20:7, “Now on the first day of the week, WHEN THE DISCIPLES CAME TOGETHER TO BREAK BREAD…” This does NOT mean believers are now limited to remembering the Lord Jesus in His death for us on Sunday. In 1st Corinthians 11:23-26 the apostle Paul wrote the following words, “For I received from the Lord what which I also delivered to you: that the Lord Jesus on the same night in which He was betrayed took bread; and when He had given thanks, He broke it and said, ‘Take, eat; this do in remembrance of Me.’ In the same manner He also took the cup after supper, saying, ‘This cup is the new covenant in My blood. This do, AS OFTEN AS YOU DRINK IT, in remembrance of Me.’ For AS OFTEN AS YOU EAT THIS BREAD AND DRINK THIS CUP, you proclaim the Lord’s death till He comes.”

You ask, “Is it a sin not to?” If your question is dealing specifically with the DAY we break bread, we have seen that we are free to break bread on ANY DAY, as OFTEN as the Spirit of God leads us to. Perhaps your question isn’t speaking of the DAY, but rather the ACT of breaking bread itself. In other words, you are wondering if it is a sin to NOT break bread. I have to two responses to that: 1) When the Lord Jesus said, “Do this, in remembrance of Me” He was ASKING US to do this; He was NOT COMMANDING US. 2) What believer would refuse to respond to our Lord’s blessed REQUEST when we owe every blessing, for time and eternity, to Him for laying down His life at Calvary so our sins could be forgiven? (284.7) (DO)