Search me, O God - The word “search” here is the same as in Psalms 139:1. See the notes at that verse. The psalmist had stated the fact that it is a characteristic of God that he “does” search the heart; and he here prays that God “would” exercise that power in relation to himself; that as God could know all that there is within the heart, he would examine him with the closest scrutiny, so that he might be under no delusion or self-deception; that he might not indulge in any false hopes; that he might not cherish any improper feelings or desires. The prayer denotes great “sincerity” on the part of the psalmist. It indicates also self-distrust. It is an expression of what all must feel who have any just views of themselves - that the heart is very corrupt; that we are liable to deceive ourselves; and that the most thorough search “should” be made that we be “not” deceived and lost.
And know my heart - Know or see all that is within it.
Try me - As metal is tried or proved that is put to a “test” to learn what it is. The trial here is that which would result from the divine inspection of his heart.
And know my thoughts - See what they are. The word rendered “thoughts” occurs only in one other place, Psalms 94:19. The idea is, Search me thoroughly; examine not merely my outward conduct, but what I think about; what are my purposes; what passes through my mind; what occupies my imagination and my memory; what secures my affections and controls my will. He must be a very sincere man who prays that God will search his thoughts, for there are few who would be willing that their fellow-men, even their best friends, should know all that they are thinking about.