So you agree that you are not following the sabbath commandment when you worship on Sunday?
It’s no longer binding. Sunday replace Saturday, Jesus is the Lord of the Sabbath, and the Apostles knew this as mention in Acts.
Therefore to miss Mass with full consent, full acknowledgement, and grave matter is a mortal sin. Jesus granted His Church to be authoritiative.
These teachings are taught not only in the Bible but in the writings of the ECF.
On the Lord’s own day, assemble in common to break bread and offer thanks, but first confess your sins so that your sacrifice may be pure." Didache, 14 (A.D. 90).
“If, therefore, those who were brought up in the ancient order of things have come to the possession of a new hope, no longer observing the Sabbath, but living in the observance of the Lord’s Day, on which also our life has sprung up again by Him and by His death–whom some deny, by which mystery we have obtained faith, and therefore endure, that we may be found the disciples of Jesus Christ, our only Master.” Ignatius, To the Magnesians, 9:1 (A.D. 110).
“The seventh day, therefore, is proclaimed a rest–abstraction from ills–preparing for the Primal Day,[The Lord’s Day] our true rest; which, in truth, is the first creation of light, in which all things are viewed and possessed. From this day the first wisdom and knowledge illuminate us. For the light of truth–a light true, casting no shadow, is the Spirit of God indivisibly divided to all, who are sanctified by faith, holding the place of a luminary, in order to the knowledge of real existences. By following Him, therefore, through our whole life, we become impossible; and this is to rest.” Clement of Alexandria, Stromata, 6:16 (A.D. 202).
“In fine, let him who contends that the Sabbath is still to be observed as a balm of salvation, and circumcision on the eighth day because of the threat of death, teach us that, for the time past, righteous men kept the Sabbath, or practiced circumcision, and were thus rendered “friends of God.” For if circumcision purges a man since God made Adam uncircumcised, why did He not circumcise him, even after his sinning, if circumcision purges? At all events, in settling him in paradise, He appointed one uncircumcised as colonist of paradise. Therefore, since God originated Adam uncircumcised, and inobservant of the Sabbath, consequently his offspring also, Abel, offering Him sacrifices, uncircumcised and inobservant of the Sabbath, was by Him commended; while He accepted what he was offering in simplicity of heart, and reprobated the sacrifice of his brother Cain, who was not rightly dividing what he was offering. Noah also, uncircumcised–yes, and inobservant of the Sabbath–God freed from the deluge. For Enoch, too, most righteous man, uncircumcised and in-observant of the Sabbath, He translated from this world; who did not first taste death, in order that, being a candidate for eternal life, he might by this time show us that we also may, without the burden of the law of Moses, please God.” Tertullian, An answer to the Jews, 2 (A.D. 203).