NOTES for Lev 5:1-19
Among the things that defile a person, the book of Leviticus also mentions a rash oath. The situation in view is when a person made a vow to God without thinking about the consequences. Like, for example, Israel's first king Saul: he made a vow to God that in the event of victory over the enemy he would sacrifice to Him the first thing that came out to meet Saul from the gates of his house, and the first to come out to meet him was his own daughter. A special purification sacrifice is provided precisely for cases of this kind. It would seem that foolishness is not a sin for which one must repent. Although one sometimes has to regret foolish things one has done, but that is another subject.
Meanwhile, the purification sacrifice in this case has a quite definite meaning, and it is not connected with atoning for human foolishness. The issue is rather the freeing of a person from the vow he has made. God, of course, does not accept promises from a person if their fulfillment is connected with violating the commandments He has given, and He does not need the fulfillment of a vow that violates His will. A person, however, often feels obliged to fulfill a vow he has made at any cost, as Saul did in the example mentioned.
In this case it was hardly worth making such an indefinite vow at all, but even after making it, there was absolutely no need to fulfill it the way Saul decided to fulfill it. To Saul himself, meanwhile, it was obvious: the vow had to be fulfilled, otherwise things would go badly. Here there is not so much faith as superstition, and it is precisely superstition that often forces a person to perform "religious" actions that he will later regret.
In this case the sin began not when Saul began to insist on sacrificing his own daughter, and not even when he made the rash vow. It began with Saul's very attitude toward the vow as something self-sufficient and separate from God, as something that acts by itself and can fall upon a person with all its hostile force if the promised thing is not fulfilled.
Here is paganism in its pure form, and this is exactly the paganism from which a person must be cleansed. Cleansing is possible because a person does not recognize this kind of vow as something pagan; if he did recognize it, he would very possibly never have made such a vow. This is precisely an involuntary sin, the kind from whose consequences one can be cleansed. If, of course, one turns to God in time.