diff --git a/macros.in b/macros.in
index 2f6ec68..5246b84 100644
--- a/macros.in
+++ b/macros.in
@@ -50,7 +50,7 @@
 %__mv			@__MV@
 %__patch		@__PATCH@
 %__perl			@__PERL@
-%__python		@__PYTHON@
+%__python		%{error:attempt to use unversioned python, define %%__python to %{_bindir}/python2 or %{_bindir}/python3 explicitly}
 %__restorecon		@__RESTORECON@
 %__rm			@__RM@
 %__rsh			@__RSH@