It is easy to say such things when life goes smoothly with us. But this Psalmist, whether David or another, says this, and means it, when all things are dark and frowning around him. The superscription attributes the words to David himself, fleeing from Saul, and hiding in the cave. Whether that be so or no, the circumstances under which the Psalmist sings are obviously those of very great difficulty and oppression. But he sings himself into confidence and good cheer. In the dark he believes in the light. There are some flowers that give their perfumes after sunset and are sweetest when the night dews are falling. The true religious life is like these. A heart really based upon God, and at rest in Him, never breathes forth such fragrant and strong perfume as in the darkness of sorrow. The repetition of 'My heart is fixed' adds emphasis to the expression of unalterable determination. The fixed heart is resolved to 'sing and give praise' in spite of everything that might make sobs and tears choke the song. I. Note the fixed heart. The Hebrew uses the metaphor of the 'heart' to cover a great deal more of the inward self than we are accustomed to do. We mainly mean thereby that in us which loves. But the Old Testament speaks of the 'thoughts and intents' as well as the 'affections' of the heart. And so to this Psalmist his 'heart' was not only that in him which loved, but that which purposed and which thought. When he says 'My heart is fixed' he does not merely mean that he is conscious of a steadfast love, but also and rather of a fixed and settled determination, and of an abiding communion of thought between himself and God. And he not only makes this declaration as the expression of his experience for the moment, but he mortgages the future, and in so far as any man dare, he ventures to say that this temper of entire consecration, of complete communion, of fixed resolve to cleave to God, which is his present mood, will be his future whatever may wait his outward life then. The lesson from that resolve is that our religion, if it is worth anything, must be a continuous and uniformly acting force throughout our whole lives, and not merely sporadic and spasmodic, by fits and starts. The lines that a child's unsteady and untrained hand draws in its copy-book are too good a picture of the 'crooked, wandering ways in which we live,' in so far as our religion is concerned. The line should be firm and straight, uniform in breadth, unvarying in direction, like a sunbeam, homogeneous and equally tenacious like an iron rod. Unless it be thus strong and uniform, it will scarcely sustain the weights that it must bear, or resist the blows that it must encounter.