Judge me, O Lord - That is, determine in regard to my case whether I am truly thy friend, or whether the evidences of my piety are genuine. The psalmist asks an examination of his own case; he brings the matter before God for Him to decide; he submits the facts in regard to himself to God, so that He may pronounce upon them whether they constitute evidence of real piety.
For I have walked in mine integrity - On the word “walk,” see the notes at Psalms 1:1. The word “integrity” here is the same which is elsewhere rendered “perfection.” See the notes at Job 1:1. Compare Psalms 37:37. See also Psalms 7:8; Psalms 25:21; where the word is rendered, as here, “integrity.” It means here “uprightness, sincerity.” This is the first thing which he brings before God for him to examine - the consciousness that he had endeavored to live an upright life; and yet it is referred to as if he was sensible that he “might” have deceived himself, and therefore, he prays that God would determine whether his life had been really upright.
I have trusted also in the Lord - Of this, likewise, he felt conscious; but this too he desired to submit to God. Trust in Yahweh, and an upright life, constituted the evidence of piety, or were the constituents of true religion according to the views of the Hebrews, as they are the constituents of true religion everywhere; and the purpose of the psalmist was to ascertain whether his piety was really of that character.
Therefore I shall not slide - If these are really traits of my character, if I really possess these, I shall not be moved. My feet will be firm, and I shall be secure. Or this may be regarded as a further declaration in regard to himself, as indicating firm confidence in God, and as meaning that he was conscious that he would not be moved, or would not swerve in this purpose of life. And yet the next verse shows that, with all this confidence as to his own character, he felt that there was a “possibility” of his having deceived himself; and, therefore, he pleaded that God would search and test him.