It seems to be a growing trend (or maybe I’m just noticing it more). There will be some kind of event at the church building on Saturday–like a seminar, lectureship, singing, service project, funeral, wedding, etc. The event may last for a few hours that Saturday. And here’s the part I want you to 
consider–there will be some members of the church who will attend that Saturday event and then not come to worship on Sunday. Their thinking sometimes (whether specifically verbalized or not) is, “I was just there on Saturday! That’s enough for one weekend!”
Brethren, if those thoughts have ever been yours, may I plead with you to consider that an event on Saturday (no matter how spiritual it is or how worship-like it is) is NOT first-day-of-the-week worship? God’s will (and that’s what matters) is for Christians to assemble every first day of the week with the church to worship Him (John 4:23-24; 20:19, 26; Acts 2:42; 20:7; 1 Cor. 16:1-2; Heb. 10:25). I should want to fit my schedule to God’s schedule more than I want to fit my schedule to anything else! Please think about it.