[mandeepj]

"What was changed is easily seen in the commit itself, why needs to be in the commit message."

Commit message is like subject of an email. Is n't it faster to look at commit message, and get an idea about change rather than go through commit and understand it?

[JohnFen]

The first line of the commit message should be the "subject line". The rest of the commit message should contain a summary of the high-level stuff such as the "why".

[bonestamp2]

Yes, fair enough... having both in the commit message is ideal. I just mean that the absolute minimum is the why because at least the what can be deconstructed from the commit.