diff --git a/builtin/commit.c b/builtin/commit.c
index 8685c88..e69f466 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1430,7 +1430,7 @@ static void print_summary(const char *prefix, const struct object_id *oid,
 	struct strbuf author_ident = STRBUF_INIT;
 	struct strbuf committer_ident = STRBUF_INIT;
 
-	commit = lookup_commit(oid->hash);
+	commit = lookup_commit(oid);
 	if (!commit)
 		die(_("couldn't look up newly created commit"));
 	if (parse_commit(commit))
@@ -1654,7 +1654,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	if (get_sha1("HEAD", oid.hash))
 		current_head = NULL;
 	else {
-		current_head = lookup_commit_or_die(oid.hash, "HEAD");
+		current_head = lookup_commit_or_die(&oid, "HEAD");
 		if (parse_commit(current_head))
 			die(_("could not parse HEAD commit"));
 	}