The book investigates the qatal//yiqtol (yiqtol//qatal) verbal sequence, previously known as 'tense shifting', as found in couplets of the Hebrew Psalter, attempting an innovatory explanation by means of M.A.K. Halliday's Systemic Theory. This study argues that qatal and yiqtol verbal forms, when part of the qatal//yiqtol verbal sequence in Psalms' poetic couplets, can be used primarily for aesthetic reasons, with no individual reference to time or aspect. Arguably, the Systemic Functional Grammar analysis of lexicogrammar can provide a comprehensive interpretation of form and function and an integrated approach to phonetics, morphology and syntax.