Albert Barnes Commentary Psalms 101:4

"A perverse heart shall depart from me: I will know no evil thing." — Psalms 101:4 (ASV)

A froward heart shall depart from me - The word translated here as 'froward' means perverse, false, deceitful, or depraved. See the notes at Psalms 18:26. The 'idea' here is that of someone 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 that might be used to persuade 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 first sense, it would mean that he would not himself be perverse and 'froward'; in the second sense, that he would not have such persons in his employ. The context seems to require that we understand it in the second sense, as referring to the type of persons the psalmist would have around him.

I will not know a wicked person - I will not approve of such a person; I will not recognize such a person among those admitted into my house, or accept him as my friend; or, I will not have such people 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:

• I will not approve of or recognize as 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 might be their rank, their wealth, their accomplishments, their charm, or their power of conversation.
• I will have in my employ no one who is not honest, temperate, virtuous, and pure.

The welfare of a family depends more on the first of these principles than the second; no family can be well-ordered where both are not found.