For a fixed heart I must have a fixed determination, and not a mere fluctuating and soon broken intention. I must have a steadfast affection, and not merely a fluttering love, that, like some butterfly, lights now on this, now on that, sweet flower, but which has a flight straight as a carrier pigeon to its cot, which shall bear me direct to God. And I must have a continuous realisation of my dependence upon God, and of God's sweet sufficiency, going with me all through the dusty day. A firm determination, a steadfast love, a constant thought, these at least are inculcated in the words of my text. 'My heart is fixed, O God! my heart is fixed.' Ah, brethren! how unlike the broken, interrupted, divergent lines that we draw! Our religious moments are not knit together, and touching one upon the other, but they are like the pools in the bed of a half dried up Australian stream--a pond here, and a stretch of white, blistering pebbles there, and then a little drop of water, and then another reach of dryness. They should all be knit together by one continuous flow of a fixed love, desire, and thought. Is our average Christianity fairly represented by such words as these of my text? Do they not rather make us burn with shame when we think that a man who lived in the twilight of God's revelation, and was weighed upon by distresses such as wrung this psalm out of him, should have poured out this resolve, which we who live in the sunlight and are flooded with blessings find it hard to echo with sincerity and truth? Fixed hearts are rare amongst the Christians of this day. II. Notice the manifold hindrances to such a uniformity of our religious life. They are formidable enough, God knows, we all know it, and I do not need to dwell upon them. There is, for example, the tendency to fluctuation which besets all our feelings, and especially our religious emotions. What would happen to a steam-engine if the stoker now piled on coals and then fell asleep by the furnace door? One moment the boiler would be ready to burst; at another moment there would be no steam to drive anything. That is the sort of alternation that goes on amongst hosts of Christians to-day. Their springtime and summer are followed certainly by an autumn and a bitter winter. Every moment of elevation has a corresponding moment of depression. They never catch a glimpse of God and of His love brighter and more sweet than ordinary without its being followed by long weariness and depression and darkness. That is the kind of life that many of you are contented to live as Christian people.