There is a difference tough, a very subtle one. A commit body should describe the rationale of the change, i.e. any decisions that had to be made or trade-offs

There is a difference tough, a very subtle one. A commit body should describe the rationale of the change, i.e. any decisions that had to be made or trade-offs in light of developer discussions and so on. Basically a description of the issue being solved. These things are rarely needed in the code itself, as the code will most likely feature new things and the old things are history. Some commits even feature implementation details, and those I agree with you sometimes it makes sense to include them in the code. However most implementation details replace old ones, and this is transition should be explained in a commit since this is the perfect place for it. Here is an random example from the linux kernel, which is guaranteed to do what I described: http://goo.gl/QdKNnJ http://goo.gl/QdKNnJ