A froward heart shall depart from me - The word here rendered froward means perverse, false, deceitful, depraved. See the notes at Psalms 18:26. The “idea” here is that of one who is inclined to evil; who has some wrong passion or inclination to indulge; who has an obstinate and perverse will; who does not listen to reason or the voice of wise persuasion; who will do wrong, despite all the means which may be employed to induce him to do right. The language may either refer to the author of the psalm himself, as regulating his own conduct; or it may refer to those in his employ. In the former sense, it would mean that he would not himself be perverse and froward; in the latter sense, that he would not have such persons in his employ. The connection seems to require that we should understand it in the latter sense, as referring to the class of persons that the psalmist would have about him.
I will not know a wicked person - I will not countenance such a one; I will not recognize such a one among those who are admitted into my house, or own him as my friend; or, I will not have such in my employ. Probably the language embraces both these ideas - as it should in the case of all who are at the head of a family:
(a) I will not countenance or recognize as among my friends, who are to be admitted to my fireside and family, and who are to be familiar with me and my children, those who are profligate, wicked, and unprincipled, whatever may be their rank, their wealth, their accomplishments, their fascination of manner, or their power of conversation;
(b) I will have in my employ no one who is not honest, temperate, virtuous, pure. The welfare of a family depends more on the former of these things than the latter; no family can be well ordered where both are not found.