I've seen church after church begin to hold worship services on Saturdays or during the midweek. This would not be an issue if these services were being offered in addition to Sunday worship services. But that is not what has been happening for the past handful of decades. Unfortunately, we in the American church do not have people busting down the doors to hear biblical preaching and to receive the Lord's Supper more than once a week. This is made evident by the near extinction of the, once ubiquitous, Sunday evening service. No, the motivation behind these "alternative" services, that is alternative to Sunday services, is virtually the opposite of a heightened devotion to worship.
These services are offered on weekdays and Saturdays for the convenience of the worshipper. The typical advocate of theses services will say something like this: "It's more convenient for my schedule to fit worship in on Saturday night or Tuesday evening than to go through the trouble of waking up on Sunday morning." Why is it that these alternative services are relatively new in church history? Surely people of past generations, who didn't have our modern technology, were equally as busy as we are. Were they just not as clever? Or was it that these fathers and mothers in the faith had substantive reasons for worshipping on Sunday? Let's try consulting one of those dusty old catechisms, which have fallen into disrepute but at one time guided Christian doctrine and piety (i.e. Christian living).
In the Westminster Larger Catechism (116), we are told that the fourth commandment (Deut. 5:12-14) requires the "keeping holy to God such set times as he has appointed in his Word, expressly one whole day in seven (Gen. 2:2-3); which was the seventh from the beginning of the world to the resurrection of Christ, and the first day of the week ever since, and so to continue to the end of the world; which is the Christian Sabbath, and in the New Testament called the Lord's Day (Acts. 20:7; Rev. 1:10)."
Here is why we worship on Sunday, or the “Lord's Day”:
1. God appoints His own day. Plenty of God's commands are inconvenient, but that is what makes God the Lord of our lives, not us. We shape our lives to conform to his commands, not the other way around. The Lord's Day is appointed by the Lord. It just makes sense, doesn't it?
2. Sunday, or the Lord's Day, is the Christian, new covenant, Sabbath. The Sabbath day has changed from the last to the first day of the week in order to commemorate the resurrection of Jesus Christ. Sunday is to be viewed as a weekly holy day (aka holiday). This doesn't mean that every sermon is an "Easter sermon" or that every Bible reading mentions the resurrection. Rather, conducting our services on Sunday intentionally orients the church's worship around the powerful reality of Christ's resurrection (read 1 Corinthians 15 to hear Paul speak about the implications of the resurrection).
3. The church should feel no need to shape its message and its practices to fit the sensibilities of the unbelieving world. We Christians must remember that the Kingdom of God will overcome the unbelieving world. Christian worship has historically included a recitation of the Lord's Prayer and the administration of the Lord's Supper. In the Lord's Prayer, Jesus teaches us to pray for God's Kingdom to come on earth as it is in heaven. This radical prayer calls on God to rule and reign over human hearts here, in this world. It is not a prayer of escape; rather it is a prayer of dominion. Often, when pastors administer communion, they read 1 Corinthians 11, where the church is commanded to participate in communion "until he [Jesus] comes." We, the church, are waiting for Jesus to come and (re)make this earth into our heaven. The church is the representation of God's Kingdom on earth now. We are the embassy of His Kingdom. Therefore, the worship of the church should confidently participate in activities that come into friction with the norms of the rebellious kingdom of man. God's Kingdom is here and His Kingdom is coming here, on earth as it is in heaven.
4. The church looks more divided and confused when we worship on different days. As you can see from what has already been said, the day that we worship is inescapably theological. When a local church disregards the deep theology of the Lord's Day, it is making a statement against the historical theology of the church.
Ask yourself, is all of this worth risking for the sake of convenience?