Since Jim and I discussed feet washing in the comments section of the last blog, I decided to go this direction for tonight. I realize what I will say below will open me to a lot of criticism from friend and foe, but I believe it is something that deserves more than the passing thought most of us give it.
In my opinion, to be fixated on the idea of "only two ordinances" goes beyond what we can prove by the Scriptures. Again, IMO, a certain amount of contrivance is needed to defend the "only two ordinances" position. Baptism and the Lord’s supper are not termed ordinances in the New Testament, as far as I can tell. There is a problem with most attempts to answer "why only two ordinances?" Our approach is something like this: We see that baptism and the Lord's supper are observances that stand out in significance and frequency more than any other rites or symbols in the New Testament, from feet washing to the holy kiss. Then we try to find ways to define and categorize this -- to make them stand out and explain why they do. First, it is said there are two ordinances -- baptism and the Lord's supper. Then it is said that baptism and the Lord's supper speak of who Christ was and what He did. So, ordinances speak of who Christ was and what He did, and therefore, there are two ordinances. This is a round of circular reasoning that assumes what we are asked to prove.
Because this is the prominent view today, many folks believe that all Baptists have always held that there are only two ordinances. Of the earliest known English Baptist confessions, some use the term "ordinance" and some do not. The Philadelphia Confession of Faith, first adopted by Baptists in America in 1742, added two articles to the former London Confession of Faith. In these two articles, they identified singing of psalms and laying on of hands as "ordinances".
There were other rites observed by the early church -- right hand of fellowship, laying on of hands, feet washing, holy kiss, anointing with oil, headcovering, and others. I do not see any reason that observing these, if a church so chooses, poses any threat to the value and importance of baptism and the Lord's supper. Baptists almost universally observe some form of the right hand of fellowship and laying on of hands.
Why two ordinances? Because most Baptists so define them and so say. It is Biblical enough to just say that baptism and the Lord's supper are pre-eminent in meaning and practice, without denying that other symbols had meaning to the apostles and the early church.