The psalmist is so thoroughly possessed by the thought of his personal relation to God that his meditation spontaneously takes the form of address to Him. That form adds much to the impressiveness, but is no rhetorical or poetic artifice. Rather, it is the shape in which such intense consciousness of God cannot but utter itself. How cold and abstract the awestruck sentences become, if we substitute "He" for "Thou," and "men" for "I" and "me"! The first overwhelming thought of God's relation to the individual soul is that He completely knows the whole man. "Omniscience" is a pompous word, which leaves us unaffected by either awe or conscience. But the psalmist's God was a God who came into close touch with him, and the psalmist's religion translated the powerless generality of an attribute referring to the Divine relation to the universe into a continually exercised power having reference to himself. He utters his reverent consciousness of it in ver. 1 in a single clause, and expands that verse in the succeeding ones. "Thou hast searched me" describes a process of minute investigation; "and known [me]," its result in complete knowledge. That knowledge is then followed out in various directions, and recognised as embracing the whole man in all his modes of action and repose, in all his inner and outward life. Vv. 2 and 3 are substantially parallel. "Down-sitting" and "up-rising" correspond to "walking" and "lying down," and both antitheses express the contrast between action and rest. "My thought" in ver. 2 corresponds to "my ways" in ver. 3,--the former referring to the inner life of thought, purpose, and will; the latter to the outward activities which carry these into effect. Ver. 3 is a climax to ver. 2, in so far as it ascribes a yet closer and more accurate knowledge to God. "Thou siftest" or _winnowest_ gives a picturesque metaphor for careful and judicial scrutiny which discerns wheat from chaff. "Thou art familiar" implies intimate and habitual knowledge. But thought and action are not the whole man. The power of speech, which the Psalter always treats as solemn and a special object of Divine approval or condemnation, must also be taken into account. Ver. 4 brings it, too, under God's cognisance. The meaning may either be that "There is no word on my tongue [which] Thou dost not know altogether"; or, "The word is not yet on my tongue, [but] lo! Thou knowest," etc. "Before it has shaped itself on the tongue, [much less been launched from it], thou knowest all its secret history" (Kay).