What the Lord is Saying: An initial though here is thinking about those groups that want to pattern themselves off of the early church often don't realize that the scripture of the early church was often the Old Testament scriptures. So there would have been teaching of the Old Testament scriptures by the apostles as well as new revelation given by Christ. My guess is the sermon on the Mount was probably a big part of that teaching since it is probably the message that Jesus repeated the most.
This verse in Acts mentions that the church devoted themselves to the apostles teaching and to fellowship. And also breaking of bread and to prayer. Even today, we want to mirror these practices. And yet I wonder if there becomes a desire by many to group these practices into almost a checklist of things that must be done by participants when people gather. I think checklist Christianity is a big concern because it becomes more about doing the checklist than exploring the relationship with Jesus.
A couple of days ago I gave a ride to Albuquerque from Durango an engaged couple after I attended a wedding with them. As we discussed things, the gal asked me about the difference between Methodist and Baptist. It was an interesting question and one in which I found myself being stumped answering. From her perspective, having grown up attending non-denominational churches, she really did not understand the different between the two churches or beliefs and I found that I struggled in explaining it.
And yet each of the denominations we have (Baptist, Lutheran, Presbyterian, Methodist, etc.) is really a product of a group of people that have come together to agree on a structure of how the Bible is to be applied and lived out and how worship is to be conducted each time people gather for worship -- after the reformation. I mention that because it seems that this idea of the application of sacraments is a chief reason for those different manifestations of churches or different denominations. Even those that call themselves non-denominations come together to agree upon something.
I referred to my Oxford Dictionary on the subject of Sacrament. It is a term not found in the Bible - but by the 3rd century was being used to describe baptism and the Lord's Supper or Eucharist. Later in the 16th century, at a time when the Reformation was occurring and Protestantism was becoming more prominent - the Council of Trent of 1564 defined 7 sacraments. The Council of Trent was the formal Roman Catholic reply to the doctrinal challenges of the Reformation. These sacraments are Eucharist, Penance, Extreme Unction, Holy Orders, and Marriage. Again, hopefully the practice of these is not simply to perform a checklist but rather to experience the relation or encounter between God and human beings.
As I personally think of these sacraments in my life and how I maybe grew up performing them (attending a Baptist church most of the time the emphasis was on baptism and Lord's Supper) - for me these acts represented an identification of my union with Christ - baptism and the Lord's Supper was an identification or union with Christ's death and resurrection. Baptism was a one time experience whereas the Lord's Supper was more often. Currently, I am content in this. Also, for both of these they are done in community - with others and with Christ. There is a community testimony of sorts that occurs. I'm not sure if I see a problem with expanding these acts if churches have more of them as long as they remain an experience to identify with Christ and other believers.
I do not think these are requirements of salvation, but I also think they are things the Christian would want to do as they encounter God.
Summary: In our sacraments, we worship God, encountering God as we identify with Christ. At a minimum these acts should include baptism and Lord's Supper.