of messianic Psalm 18 and Torah Psalm 19; and (4) the contribution of acrostic psalms to the structure of Book I. The introductory role of these two psalms has already been discussed. But their significance across the whole Psalter deserves further consideration. Taken together, these two psalms define the substance of essentially all that will follow throughout the remainder of the Psalms. The first psalm declares the critical character of the law; the second