18:18 So Paul still remained a good while. Then he took leave of the brethren and sailed for Syria, and Priscilla and Aquila were with him. He had his hair cut off at Cenchrea, for he had taken a vow. 19 And he came to Ephesus, and left them there; but he himself entered the synagogue and reasoned with the Jews. 20 When they asked him to stay a longer time with them, he did not consent, 21 but took leave of them, saying, “I must by all means keep this coming feast in Jerusalem; but I will return again to you, God willing.” And he sailed from Ephesus.
Let me begin with a humbling story. It will all make sense in the end. If it doesn't you know where to find me. ;)
Our local Canadian Tire store is a frequent handy man stop. In the auto parts department one of the associates is female, about 20 years old, hair of several bright shades, multiple piercings etc... Of course my religious upbringing judged her and quite harshly. I assumed she would know little to nothing about cars/parts etc... she was likely on drugs, and I'd be better off with anyone else helping me. We'll did I ever get a surprise. God has to 'slap us around' sometimes. She turned out to be the most helpful and knowledgeable person in the whole department. I have come to be so impressed by her that when I go there I look for her if I need a hand. Last week I even called for a manager and told her that girl is the best employee in the whole store. Now back to Paul...
We could speculate for hours but I've yet to find an explanation for what vow Paul made and why he made it and why it involved cutting his hair. One thing we do know is that it was not a Nazarite vow because the details don't fit. You can read about that in Numbers 6.
However since we're on the topic of vows the Bible has two things to say about them. The first is that if you make a vow, you should keep it. The second is straight from the lips of Jesus and He infers we are far better off not making any vows at all. I mean think about it. How do we know we'll be able to keep a vow even if we intend to?
It's interesting that Paul's vow involved shaving his hair off. There is an obscure law (one of many) in Leviticus that forbids shaving the hair on the sides of the head yet Paul did. Also in that list of obscure laws is the command to not wear clothing that has mixed materials in it. Tattoos are also forbidden.
What are we to make of those laws that are stated once and never repeated? Clearly Paul didn't feel held by them. What's even more curious to me is that some will hold to one or more of those laws while completely ignoring other ones.
What it all says to me is that we struggle to look at the big picture. We make decisions about what "rules" we will follow that have no consistency or basis in logic. This is a problem. Wouldn't it be wiser to seek to understand those old laws in their context and then seek to hold onto the principle?
For example Samson lived under the Nazirite vow which forbid cutting the hair at all. Paul takes a vow that involves cutting all his hair. Leviticus says not to cut the hair on the sides of the head. That is three distinctly different hair styles. Clearly God has no set law for hair. Why would He? Nature is full of variety. Some animals have very long hair, some short hair, some no hair, while a male lion has short and long hair.
Bad religion fixates on these issues. Jesus did not. Jesus was concerned with something much more basic and important: live with integrity. That's why He advised not making vows. It's much easier to live with integrity if you don't make promises that circumstances might prevent you from keeping. Paul did make a vow and he kept it. That's the important part. Live with integrity before God.