This shows that the first day of the week immediately followed the Sabbath; but the Sabbath was all past before the first day of the week began. Although they came “very early in the morning the first day of the week,” there was no Sabbath there. They could not have found it if they had been looking for it; but they were not looking for it, because they had kept it the day before, “according to the commandment.”
Instead of attacking their error and combating it with hard argument, the apostle begins with an experience, which illustrates the case in hand. In this narrative he shows that salvation is wholly by faith for all men alike, and not in any degree by works. As Christ tasted death for every man, so every man who is saved must have Christ's personal experience of death and resurrection and life. Christ in the flesh does what the law cannot do. Galatians 2:21; Romans 8:3,4
All your toiling to do better and to obey the law, will do no good; for it is not your righteousness that is called for; it is God’s righteousness. It is not your righteousness that is demanded by the law; it is God’s. It is not your righteousness that will be accepted by the law; it is God’s righteousness alone that will be accepted. It matters not how hard you try, nor how much you do, the law will never witness to your righteousness; the law will witness only to the righteousness of God. --A. T. Jones