Reproduction of the original: The Expositor’s Bible: The Psalms, Vol. 1 by A. Maclaren

1 Happy the man who has not walked in the counsel of the wicked, And has not stood in the way of sinners, And in the session of scorners has not sat. 2 But in the law of Jehovah [is] his delight, And in His law he meditates day and night. 3 And he is like a tree planted by the runnels of water, Which yields its fruit in its season, And whose leafage does not fade, And all which he does he prosperously accomplishes. 4 Not so are the wicked, But like chaff which the wind drives away. 5 Therefore the wicked shall not stand in the judgment, Nor sinners in the congregation of the righteous. 6 For Jehovah knows the righteous, And the way of the wicked shall perish. The Psalter may be regarded as the heart's echo to the speech of God, the manifold music of its wind-swept strings as God's breath sweeps across them. Law and Prophecy are the two main elements of that speech, and the first two psalms, as a double prelude to the book, answer to these, the former setting forth the blessedness of loving and keeping the law, and the latter celebrating the enthronement of Messiah. Jewish tradition says that they were originally one, and a well-attested reading of Acts xiii. 33 quotes "Thou art my Son" as part of "the first Psalm." The diversity of subject makes original unity improbable, but possibly our present first Psalm was prefixed, unnumbered. [Pg 2] Its theme, the blessedness of keeping the law, is enforced by the juxtaposition of two sharply contrasted pictures, one in bright light, another in deep shadow, and each heightening the other. Ebal and Gerizim face one another. The character and fate of the lover of the law are sketched in vv. 1-3, and that of the "wicked" in vv. 4-6.

Abstract: "We describe a theory of quantitative representations and processes that makes novel predictions about student problem-solving and learning during the transition from arithmetic to algebraic competence or 'early algebra'. Our Early Algebra Problem Solving (EAPS) theory comes in the form of a cognitive model within the ACT-R cognitive architecture. As a 'pedagogical domain theory', our EAPS theory can be used to make sense of the pattern of difficulties and successes students experience in early algebra problem solving and learning. In particular, the theory provides an explanation for the surprising result that algebra students perform better on certain word problems than on equivalent equations (Koedinger & Nathan, 2000; Nathan & Koedinger, 2000). It also makes explicit the knowledge and knowledge selection processes behind student strategies and errors and provides a theoretical tool for psychologists and mathematics educators to both productively generate and accurately evaluate hypotheses about early algebra learning and instruction. We have abstracted our development process into six model-building constraints that may be appropriate for creating cognitive models of problem solving in other domains."