The test we must apply is 'whether or not the statement was manifestly intended or was of such character that a jury would naturally and necessarily take it to be a comment on the failure of the accused to testify.' United States v. Jennings, 527 F.2d 862, 871 (5th Cir.1976), quoting United States v. Wilson, 500 F.2d 715, 721 (5th Cir.1974), cert. denied, 420 U.S. 977, 95 S.Ct. 1403, 43 L.Ed.2d