There are two methods to do what you want, depending on exactly what you want.
The first and shortest is to use gitrevisions syntax to specify the "first" revision that contains a given string in its commit message:
git rev-parse :/65243
and:
git show :/65243
Quoting from the documentation linked above:
A colon, followed by a slash, followed by a text, names a commit whose commit message matches the specified regular expression. This name returns the youngest matching commit which is reachable from any ref. If the commit message starts with a ! you have to repeat that; the special sequence :/!, followed by something else than !, is reserved for now. The regular expression can match any part of the commit message. To match messages starting with a string, one can use e.g. :/^foo.
This form of expression names a specific commit (i.e., it has the same usage as a raw SHA-1 ID), which is why git rev-parse will show you the revision-ID and git show will show you the commit itself.
If that picks the wrong revision, use git log --grep=65243 to limit its output to those commits that contain the specified regular expression in their commit messages. The difference is that this looks only at the same revisions that git log would show otherwise (so you may add additional limiters), and shows all matching revisions. That is, you can do things like:
git log --since=... --before=... --author=... --grep=65243 branch~30..branch
to see commits that are reachable from branch but not from branch~30, happened between the two time stamps, have the given author, and contain 65243. (Add --oneline or a --format=pretty:... string to the git log command if desired, etc.)
--grepoption which allows you to search for a string in the commit message.