There are many ups and downs in the life of the believer in Christ, and yet whom the Lord loveth he chasteneth, and scourgeth every son whom he receiveth (Heb 12:6). We see, then, in the lives of Saul vs. David how one was left alone in order to expose the false nature of his unregenerate heart, while the other was disciplined and chastised in order to reveal the true, regenerated nature of his heart. Saul, like Judas a millenium later, was led to a place of despair whereas David, like Peter, to a place of increasing obedience and faith.
As the heart grows either colder or warmer, it becomes evident who is running with patience the race that is set before us (Heb 12:1) and who is not. But how can we do this? All of us are deeply disappointing. None of us can trust his own heart. Surely it is only as we look unto Jesus the author and finisher of our faith (Heb 12:2). If we find ourselves growing cold, disobedient, fearful of the darkness of our own hearts, then how can we do anything other than turn from these things and to the Light, trusting in the glory of another, our holy Author, one who will not let us go on unfinished?
In terms of worldly goals, Saul, like a modern-day mega-church televangelist, had it all; a choice young man, goodly, higher than any of the people (1 Sam 9:2). And yet, in spiritual terms he was lifeless, dead in trespasses and sins (Eph 2:1), persecuting David without cause, turning to a witch rather than the Lord, and ultimately ending his own life through fear of what man might do to him (1 Sam 31:4). David, on the other hand, was someone who loved the Lord and, through ups and downs, was loved by Him.
By looking unto Jesus, may this year of 2015 Anno Domini be a year in which we increasingly lay aside every weight, and the sin which doth so easily beset us (Heb 12:1), to honour the Lord through faith alone.