I will instruct thee - Many interpreters have understood this to refer to God - as if he were now introduced as speaking, and as saying that he would be the guide of those who thus submitted to him, and who sought him by penitence and confession. But it is more natural to regard the psalmist as still speaking, and referring to his own experience as qualifying him to give counsel to others, showing them how they might find peace, and with what views and feelings they should come before God if they wished to secure his favor. He had himself learned by painful experience, and after much delay, how the favor of God was to be obtained, and how deliverance from the distressing consciousness of guilt was to be secured; and he regards himself as now qualified to teach others who are borne down with the same consciousness of guilt, and who are seeking deliverance, how they may find peace. It is an instance of one who, by personal experience, is fitted to give instruction to others; and the psalmist, in what follows, does merely what every converted man is qualified to do, and should do, by imparting valuable knowledge to those who are inquiring how they must be saved. Compare Psalms 51:12-13.
And teach thee in the way which thou shalt go - The way which you are to take to find pardon and peace; or, the way to God.
I will guide thee with mine eye - Margin, I will counsel thee, mine eye shall be upon thee. The margin expresses the sense of the Hebrew. The literal meaning is, “I will counsel thee; mine eye shall be upon thee.” DeWette, “my eye shall be directed toward thee.” The idea is that of one who is telling another what way he is to take in order that he may reach a certain place; and he says he will watch him, or will keep an eye upon him; he will not let him go wrong.