For thy goodness is before mine eyes. This verse may be viewed as one sentence, or divided into two parts, but with almost the same sense. If the former reading is adopted, both the verbs will be emphatic, after this manner: "Because thy goodness, O Lord, has been ever before mine eyes, and I have trusted in thy faithfulness, I have restrained all wicked lusts in my heart, lest, provoked by the malice of mine enemies, I should be forced to retaliate." By this interpretation there would be the rendering of a cause. The other exposition, also, is not unsuitable, namely, "Because thy goodness has been before mine eyes, I have walked in the truth which thou commandest." In this case the conjunction, as is common among the Hebrews, is superfluous. But although this exposition is allied to the former, I would rather prefer one less remote from the words. As it is a rare and difficult virtue, not only to refrain one's self from wicked actions, when greatly tempted thereto, but also to preserve integrity of heart; the prophet declares in what manner he pursued his course in the midst of such powerful temptations, telling us that it was by setting the goodness of God, which so carefully preserves his servants, before his eyes, lest, declining to evil practices, he might deprive himself of his protection; and by confiding in his faithfulness, he possessed his soul in patience, firmly persuaded that God would never forsake his faithful people who trusted in him. And certainly, had he not relied upon the goodness of God, he could not have so constantly prosecuted the path of integrity amidst such numerous and such severe assaults. It is, indeed, a remarkable difference between the children of God and worldly men, that the former, in the hope of a favorable issue at the Lord's hand, rely upon his word, and are not driven by restlessness to mischievous practices; while the latter, although they maintain a good cause, yet because they are ignorant of the providence of God, are hurried hither and thither; follow unlawful counsels; betake themselves to craftiness; and, in short, have no other object than to overcome evil with evil. Whence, accordingly, their miserable and sorrowful, and often their tragical ends, but because, despising the favor of God, they give themselves up to cunning and deceit? In short, David was steady in preserving his uprightness, because he had resolved that God should be his guide. In the first place, therefore, he mentions his goodness, and afterwards he adds, his truth, because his goodness, which enables us to walk with unyielding courage in the midst of all temptations, is only known to us by his promises.

For thy loving-kindness is before mine eyes - Thy favor or friendship is constantly before me, in the sense that it is the object of my desire. I wish to secure it; I long to know whether I have sufficient evidence that it is mine. This is a reason why he desires that God would search him. The favor or the friendship of God was an object of intense desire with him. He had evidence upon which he relied, and which seemed to him to be satisfactory, that God was his friend. But the object was so great, the matter was so important, the danger of self-deception was so imminent, that he did not dare to trust his own judgment, and he prayed that God would search him. The thought here is, that it was a steady purpose of his life to secure the favor of God. His eye was never turned from this. It was always before Him.
And I have walked in thy truth - I have embraced the truth; I have regulated my life by the truth. This is the first thing to which he refers. He was certain that this had been his aim. Compare the notes at 3-John 1:4. See also 2-Kings 20:3. One of the first characteristics of piety is a desire to know what is true, and to live in accordance with the truth. The psalmist was conscious that he had "arrived" at this, and that he had endeavored to make it a ruling principle in his conduct. Whether he had done this, or whether he had deceived himself in the matter, was what he now wished to submit to the all-searching eye of God.

For thy loving-kindness - A sense of thy favor and approbation was more to my heart than thrones and sceptres; and in order to retain this blessing, I have walked in thy truth.

For thy (c) lovingkindness [is] before mine eyes: and I have walked in thy truth.
(c) He shows what stayed him, that he did not recompense evil for evil.

For thy lovingkindness is before mine eyes,.... The special lovingkindness of God, shown in the choice of him in Christ, in the provision of a Saviour for him, and in the effectual calling of him; which lovingkindness is unmerited, free, and sovereign, is from everlasting and to everlasting; it is better than life, excellent beyond expression, and marvellous: and this may be said to be "before his eyes"; because it was now in sight; he had a comfortable view of interest in it, and was persuaded nothing should separate him from it; it was upon his heart, shed abroad in it, and he was affected with it; it was in his mind, and in his thoughts, and they were employed about it; he had it in remembrance, and was comfortably refreshed with it: and this he mentions as the reason of his laying his cause before the Lord, as the ground of his trust in him, and why he desired to be examined, proved, and tried by him;
and I have walked in thy truth; by faith in Christ, who is the truth of all promises, prophecies, types, and figures; in the word of truth, by abiding by it, and walking according to it; and in the truth of worship, in all the commandments and ordinances of the Lord; and to walk herein he used himself to, and was constant in, as the word (s) signifies: and nothing more engages to walk on in Christ, as he has been received and to walk as becomes his Gospel, and in all holy conversation and godliness, than the love of God manifested to the soul; this being set continually before our eyes encourages faith and hope, and influences a holy life and cheerful obedience to the will of God.
(s) "ambulavi indesinenter et sedulo", Gejerus; so Junius & Tremellius, Piscator.

As often, the ground of prayer for present help is former favor.

Psalm 26:3 tells how confidently and cheerfully he would set himself in the light of God. God's grace or loving-kindness is the mark on which his eye is fixed, the desire of his eye, and he walks in God's truth. חסד is the divine love, condescending to His creatures, and more especially to sinners (Psalm 25:7), in unmerited kindness; אמת is the truth with which God adheres to and carries out the determination of His love and the word of His promise. This lovingkindness of God has been always hitherto the model of his life, this truth of God the determining line and the boundary of his walk.

For - I dare appeal to thee, because thou knowest I have a deep sense of thy loving - kindness, by which I have been led to love and obey thee.