Is it right for the church to have devotionals, Leadership Training for Christ, retreats, summer camps for the youth, Trick or Treat at Halloween, or New Year Eve parties at the church?
A church's duty foremost is to provide the opportunity of its members to gather for worship. "... when you come together as a church" (I Corinthians 11:18). "How is it then, brethren? Whenever you come together, each of you has a psalm, has a teaching, has a tongue, has a revelation, has an interpretation. Let all things be done for edification" (I Corinthians 14:26).
Paul's statement leads us to the second duty, which is to teach -- both its members and to spread the gospel message. "And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for the edifying of the body of Christ" (Ephesians 4:11-12). That includes the support of preachers teaching the gospel. "Now you Philippians know also that in the beginning of the gospel, when I departed from Macedonia, no church shared with me concerning giving and receiving but you only. For even in Thessalonica you sent aid once and again for my necessities" (Philippians 4:15-16).
A third duty is to help its members who are in financial difficulties (Acts 2:44-45; 4:32-35; 6:1-3). Mostly the church helps with short-term disasters, such as famines, but in limited cases, it helps with long-term care (I Timothy 5:16).
For a church to be involved in something, there first needs to be given authority from the head of the church, that is Christ, before engaging in any activity. Therefore, devotionals and leadership training fall under the church's duty to teach God's word. But parties and recreation are not authorized.
Some try to get around the lack of authority by claiming to do a task that is authorized, such as holding a class for young people, while supplying pizza and soda, which are not authorized. Each thing needs to be examined to see if it is truly a part of what Christ wants the church to do. We need to remember that it is the gospel that should be the reason people come to learn, not food or entertainment. "Jesus answered them and said, 'Most assuredly, I say to you, you seek Me, not because you saw the signs, but because you ate of the loaves and were filled. Do not labor for the food which perishes, but for the food which endures to everlasting life, which the Son of Man will give you, because God the Father has set His seal on Him'" (John 6:26-27).