O my G-d, I trust in You; let me not be ashamed; let not my enemies triumph over me. Indeed, let no one who waits on You be ashamed; let those be ashamed who deal treacherously without cause.
The Midrash Tehillim (Midrash on Psalms) relates a story that offers light on these verses. One night the royal watchman seized a traveler, suspecting him of a crime. The intruder cried out, "Please don't punish me; I am a member of the king's household!" The next morning, the prisoner was brought before the king. The king asked him, "My dear son, do you even know who I am?"
The prisoner sheepishly responded that he did not know who the king was. "But I do place my trust in you, dear king, because if I did not claim to be under your protection, the guard would have beaten me to death."
The king listened to the man's words, and the expression on the king's face immediately softened. He was impressed by the fact that the man placed his trust in him. That mere fact was enough of a reason for the king to pardon him.
David, in the Psalm, begs the King for mercy for one reason: because he places his full trust in Him: "Elohai becha vetachti." And King David extends this request to include all those who trust in Hashem. Although we may not be deserving of being members of the King's "household," we still ask to be saved, for having placed out trust in Him.
David knew that he was in need of forgiveness. He also knew, that in the future, people would be in need of forgiveness. There are many times when we face what appear to be insurmountable challenges, and we keep failing. Still, we plead with the Almighty to give us another chance. He does, and because of our trust in Him, before we know it, we are able to achieve the impossible.
The alphabetical arrangement of the verses in this Psalm also indicate that David intended this psalm to be kept not only before his own eyes, but in the minds of all of the rest of mankind by constant repetition. The Sages teach us that the last verse of the psalm was added by David when he made this psalm part of Israel's national collection of hymns, as it were. Therefore, all of the preceding verses, which seemed to apply to only one individual, were now made to apply to all of Israel as well, and by extension all of mankind.
It is clear that David understands, that whatever joy or sorrow G-d decides to send his way, they are only intended to help him reach his goal of spiritual perfection which he knows he can only hope to attain with the help and guidance of G-d. David asks that the L-rd keep him from errors which would only cause his enemies to rejoice.
Those who are drawn to G-d with every fiber of their being, David reassures us, will never be deceived in their trust. On the other hand, the man who breaks faith with G-d will be grievously disappointed. Such a man will have forfeited G-d's nearness and have nothing to compensate him for his loss. Even if this man thinks he has achieved his heart's desire by breaking with Hashem and going his own way, he is in for a rude awakening. No one can achieve lasting satisfaction from the fruit of work that is not in conformity with G-d's will, especially if the price of his "success" was a breach in faith against G-d and His ways.
G-d will not forsake anyone remains capable of being taught and trained. Our Sages remind us that G-d is as upright as He is good, and as good as he is upright and that it is His desire to deal kindly with men, while at the same time desiring men to live uprightly and in conformity with His will so that He can bestow upon men the favor of His mercy. He even shows sinners who have grown old in sin, those who have grown old on the path of life, the right paths in which they must walk.
By means of His providence, He makes us realize that the paths which conform to His will, are the only ones that are good and true. At first, when we are just starting out, we may tread these paths with a sense of reluctance, but as we learn to walk them out of are own free will, we learn to do so with joy and deep devotion, because His will has now become our desire as well.
David voices his conviction in verse fifteen that the sole purpose of all of G-d's ways and dealings with us, is related to our guidance and moral improvement. "Therefore," David says with full confidence, "my eyes are always turned to G-d. I earnestly expect that he will deliver me at any moment from the tribulations that have ensnared me and that currently inhibit my progress on His path."
Let him who is convinced that his views are true and right express them . . . at every opportunity . . . without considering how much support or how much opposition he will encounter. Only falsehood is in need of many supporters in order to win the day; falsehood must have the authority of numbers to make up for what it lacks in justification. Truth, by contrast, will always prevail, even if it takes time. Noble, courageous and pure, expressed with all the fiery zeal and conviction and with all clarity of sure awareness, stated again and again at every opportunity, truth will ultimately gain respect and admiration even of those who do not accept it. The only truth that can be lost beyond recall is that truth whose adherents no longer have the courage to speak up candidly on its behalf. Truth has never gone down in defeat as the result of opposition, it has done so only when its friends are too weak to defend it. - R' S.R. Hirsch