diff --git a/builtin-diff.c b/builtin-diff.c
index 48d2fd03b79c9c03e1e32b7743f936872a3684f1..ec27542d484b8a1d69d1ea5a57ba795f5a78b35c 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -125,9 +125,6 @@ static int builtin_diff_blobs(struct rev_info *revs,
 			      int argc, const char **argv,
 			      struct blobinfo *blob)
 {
-	/* Blobs: the arguments are reversed when setup_revisions()
-	 * picked them up.
-	 */
 	unsigned mode = canon_mode(S_IFREG | 0644);
 
 	if (argc > 1)
@@ -135,7 +132,7 @@ static int builtin_diff_blobs(struct rev_info *revs,
 
 	stuff_change(&revs->diffopt,
 		     mode, mode,
-		     blob[1].sha1, blob[0].sha1,
+		     blob[0].sha1, blob[1].sha1,
 		     blob[0].name, blob[0].name);
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);