You wrote the wrong message in the last commit

Let's start with the log so that we can see the change:

Figure 12.1: Log of initial state

This one is easy; all you need do is enter:

git commit --amend

Your editor will open and allow you to change the message. To change the wording of the message just change the "pick" to "reword."

After you save your file, the message of the last commit will be changed as shown in Figure 12.2:

Figure 12.2: Log after amend (changed message in the last commit)