Christians no longer worship on Saturday But on Sunday since our Lord rose from the dead on a Sunday (John 20:1, Luke 24:1on the First day of the week), thus from then onwards Sunday became the day of Public worship for the apostles as we read in 1Corinthians 16:2 " On the First day of the week (Sunday) (in Hebrew yom rishon) every one of you must put aside what he can afford, so that collections need not be made after I have come."

The law to worship God in public one day a week has in no way been violated but rather affirmed and brought to its fullness. This is because all the covenants of the Old Law were given to God's chosen people to prepare them for the coming of their redeemer who would reign for ever (John 1:45). St. Paul makes this clear saying " These (former things of the Old Law i.e., New Moons or Sabbaths) were only pale reflections of what was coming; the reality is Christ" (Colossians 2:16-17). As baptism was the fullfilment of the Jewish circumcision (Col 2:11-12) for Christians, so to was Sunday the fullfillment of the Sabbath (Saturday). Christians must never make lightly of the price Christ paid for our redemption as for this reason does St. Paul say " I wish to know nothing but Christ and him crucified" (1 Corinthians 2:2). The early Church for this reason, adopted Sunday as the day of the Lord (Acts 20:7 "On the first day of the week") for our faith is not in sum superficial messiah but in Christ the Son of the eternal Father who died for us and rose again on the third day. Christ resurrection is an integral part of our faith as St. Paul puts it "if Christ be not risen, then our preaching is vain, and your faith is also in vain" (1 Corinthians 15:14). Thus in deed was Saturday substituted for Sunday (with divine approval) since Christ came to "fulfil the law and not abolish it" (Matt 5:17).

Sunday replaces the Sabbath as it was from hence forth especially consecrated to God by the community's worship. At times Christians celebrated their Mass in each others homes (Acts 2:42-46). We Further read that the first day of the week is the day of worship of the early Christian Community in the following : Acts 20:7 "On the first day of the week, when we were gathered together to break bread, Paul talked with them, intending to depart on the morrow; and he prolonged his speech until midnight." Here we see the two basic elements of Sunday worship which have been followed by the Church to this day: 1) the breaking of bread, which designates the celebration of the Lord's Supper (Catholics call it the Mass); and 2) the sermon. Furthermore elsewhere St. Paul told the Corinthians to contribute money to the Church each Sunday (1 Cor 16:1-2). This would be a strange request, if Christians assembled on Saturdays.

From time to time the apostles did go to synagogue on the Sabbath, however this was in order audience to preach to. It would not have even possible for them on these occasions to celebrate mass, as the Jews had certainly not assembled there to celebrate a Christian Mass.

We read that in the Gospel of Luke (Luke 24:1). "But on the first day of the week" two men were going to a village named Emmaus, were upon meeting Jesus he (Jesus) began to interpret to them in all the scriptures "the things concerning himself". Further on we read that when he was at table with them, he took the bread and blessed, and broke it, and gave it to them…(Luke1: 35) Then they told what had happened on the road, and how he was known to them in the breaking of the bread." Christ's actions signify the two elements of the Catholic Mass, namely the Lord's Supper of the Lord's and the word of God being exposed and explained to them. And He does this with the disciples on the first day of the week. An example for all Christians to follow.

It was also logical to consider Sunday as THE DAY OF THE LORD. It is by the way, the eighth day, that of the NEW Creation, restored by Jesus Death and Resurrection.

The word Sabbath as mentioned in Exodus is quite lengthy but if one reads it all we read : "Remember the Sabbath day, to keep it holy. Six days you shall labor, and do all your work; but the seventh day is a Sabbath to the Lord your God; in it you shall not do any work, you, or your son, or your daughter, your manservant, or your maidservant, or your cattle, or the sojourner who is within your gates; for in six days the Lord made heaven and earth, the sea, and all that is in them, and rested the seventh day; therefore the Lord blessed the Sabbath day and hallowed it" (Ex. 20:8-11). For the Jews the Seventh day was Saturday but if we read Exodus God doesn't mention anything about Saturday all he says is that "six days you shall labor... but on the Seventh day you shall rest." So what God is Concerned about is that, after six days of labor we should make the Seventh day, a day of rest and worship for God. Thus a Christian who works Six days and then Worships on The Seventh day (Sunday) fulfills exactly the request of God.

However St Paul answers this claim the best in that he says: (Colossians 2:16-17) "From now onwards, NEVER LET ANYONE ELSE DECIDE what should eat or drink, OR WHETHER YOU ARE TO OBSERVE ANNUAL FESTIVALS, NEW MOONS OR SABBATHS, THESE WERE ONLY PALE REFLECTIONS OF WHAT WAS COMING:THE Reality is CHRIST" In other words, Paul is saying let no one call the Christians to task for what they ate or drank or IN REGARD TO FESTIVALS: NEW MOONS (the thing of the pagans) and SABBATHS (Jews). Note also that the festival, new moon (2 kings 4:23) , and Sabbaths are references to the yearly, monthly, and weekly observances of the Mosaic calendar. Therefore the whole Jewish festal calendar is no longer binding and this includes the Sabbath's of the Old Law. Thus St. Paul rebukes the idea of reverting back to Jewish customs and observance of feast days of the Mosaic calendar as if they were still binding (Galatians 4:9-11). Today those who object to Sunday worship also place themselves under St. Paul's harsh words of condemnation

In reading the above text from St. Paul clearly one cannot say that the doing away with only applies for New moons but rather "New moons or Sabbaths". This is also because when the Old Covenant completed its usefulness and passed away so did the signs. Circumcision is no longer an obligation (Galatians 5:2). Honoring the seventh day of the week is also no longer binding. Saint Paul states that the legal demands of the Old Covenant are canceled and explicitly mentions the Sabbath as one of these (Colossians 2:14). Thus worship on Sunday is not an abolishing of the Law but a fulfillment of it as the seventh day is a sign of the glory of the Old Covenant. However, it only prefigured the glory of the New Covenant (2 Corinth 3:5-10).

Further there are other Old Testament ritual laws which are now void, no longer binding, such as circumcision, temple sacrifices, etc. Cf. Galatians 5: 2, and Acts 15. Our Lord speaks of these old Laws as passing things, when he speaks of " heaven and earth pass(ing) away" (Luke16:16-17) which refers to some sort of spiritual reality that has already occurred or is in the process of occurring. It is not a reference to the end of the world, but the coming of the new age, which occurs with the coming of the Messiah, and the New Covenant. Hebrews 9:26 "…But as it is, he (Jesus) has appeared once for all at the end of the age to put away sin by the sacrifice of himself." We are living in the new and final age that was prophesied by Isaiah as the time of the "new heavens and a new earth." Isaiah 66:22-23 "As the new heavens and the new earth which I will make Shall endure before me, says the LORD, so shall your race and your name endure. From one new moon to another, and from one Sabbath to another, All mankind shall come to worship before me, says the LORD."

In Regards to Worship Our Lord Himself Made it Clear How people Would Worship: John 4: 21 " Believe me woman, a time will come when YOU will NO LONGER Worship the Father neither on this mountain nor in Jerusalem. (Note The Jewish temple and Worship on Saturday is Were the Jews felt the real Place and Time of Worship was), You Worship what you do not know, we worship what we do know, for the Salvation is from the Jews. Yet A TIME is coming and has now come when the True worshipers will worship the Father in Spirit and Truth". Note he Says nothing about the Sabbath (Saturday) making A true worshiper.

Jesus on many occasions offended the Pharisees of his day by working on the sabbath and performing miracles (Matt 12:9-14, Luke 13:10-17, John 9:1-33 ).The Pharisees also complained that Jesus let His disciples work on the Sabbath (Matt 12: 1-8) Jesus replied Matthew 12:8 "…For the Son of man is lord of the sabbath" which provides us with a deeper understanding of Sabbath. The Pharisees criticized Jesus because they got so caught up with the ritual aspect that they missed the more important spiritual one as the Sabbath is not an end in itself. Christ knowing their hearts (Mark 2:27) "said to them, 'The sabbath was made for man, not man for the sabbath;". The Sabbath signifies two things: One, unlike the other animals we will not find our fulfillment and happiness in just working for our food and our other bodily needs because we have a spiritual as well as physical nature (Matt 4:4). Second, the purpose of man's creation is to be in a covenant relationship with God and only in Him will we find true rest for our souls and lasting happiness. We are made to love and worship God and to be united with Him in His Covenant, thus Christians now live under the New Covenant (Jeremias 31:31, Hebrews 9:15) made in the blood of Christ.

We also read in the book of revelations St John Says (Rev 1:9-10) " I am John, your brother.... I was On the island of patmos..... It was the LORD'S DAY" (in Greek: Kyriake hemera ) in Greek this designates the Sunday. We note this as the book of Revelations is a blueprint for the Sacred Liturgy of the Christian community’s weekly worship. There is the reading of the Word of God (chapters 2 -5), and the partaking of the wedding banquet of the Lamb of God, our Passover Sacrifice (chapter 19) and this takes place on the Lord’s Day.

Further many of the writings of the early Christians attest the fact that Sunday was the Day of Worship for the Christians e.g. The Didache (14:22); St. Ignatius of Antioch (around 110 AD); St. Justin of Neapolis (Holy Land, around 150), Dionysius of Corinth (around 170 AD): St. Clement of Alexandria (around 194); Melito of Sardes (beginning of the second century); Hieronymus (Jerome), Tertullian, Eusebius of Caesarea and many others.