This verse might be more strictly rendered, "Thou shalt not follow the many to evil; neither shalt thou bear witness in a cause so as to incline after the many to pervert justice."

Thou shalt not follow a multitude to do evil - Be singular. Singularity, if in the right, can never be criminal. So completely disgraceful is the way of sin, that if there were not a multitude walking in that way, who help to keep each other in countenance, every solitary sinner would be obliged to hide his head. But רבים rabbim, which we translate multitude, sometimes signifies the great, chiefs, or mighty ones; and is so understood by some eminent critics in this place: "Thou shalt not follow the example of the great or rich, who may so far disgrace their own character as to live without God in the world, and trample under foot his laws." It is supposed that these directions refer principally to matters which come under the eye of the civil magistrate; as if he had said, "Do not join with great men in condemning an innocent or righteous person, against whom they have conceived a prejudice on the account of his religion," etc.

Thou shalt not follow a multitude to [do] evil; neither shalt thou speak in a cause (a) to decline after many to wrest [judgment]:
(a) Do that which is godly, though few favour it.

Thou shalt not follow a multitude to do evil,.... The Targums of Jerusalem and Jonathan add, but to do good. As in private life, the examples of the many, who are generally the most wicked, are not to be followed, though they too often are; examples, and especially of the multitude, having great influence, and therefore to be guarded against; so in public courts of judicature, where there are many judges upon the bench, if one of them is sensible that the greater part go wrong in their judgment of a case, he ought not to follow them, or be influenced by them, but go according to the dictates of his own conscience, and the evidence of things as they appear to him, and neither agree to justify the wicked, nor condemn the righteous:
neither shall thou speak in a cause to decline after many to wrest judgment; or "thou shalt not answer" (r); either in pleading in a cause, and taking the side of it the majority is on, and for that reason, though it is a manifest perversion of justice; or by giving a vote on that side, and on that account, whereby a wrong judgment passes; and this vote given either according to the number of witnesses, which ought not always to be the rule of judgment; for it is not the number of witnesses, but the nature, evidence, and circumstances of their testimony, that are to be regarded: Jarchi says, in judgments of life and death, they go after the mouth of one witness to absolve, and after the mouth of two to condemn: or according to the number of judges on the bench, and their superiority in years and knowledge; and so some render the word, "after the great ones" (s); for a judge is not to be influenced by names or numbers in giving his vote, but to judge according to the truth of things, as they appear to him: hence the Jews say, that the younger or puisne judges used to be asked their judgment first, that they might not be influenced by others superior to them; and a like method is taken with us in the trial of a peer, the younger lords always giving their opinion first: as to the number of votes by which a cause was carried in court, it is said (t), not as the decline to good, is the decline to evil; the decline to good, i.e. to absolution, is by the sentence of one (a majority of one); the decline to evil, i.e. to condemnation, is by the mouth or sentence of two, a majority of two.
(r) "neque respondeas", Tigurine version; "non respondebis", Pagninus, Montanus, Vatablus, Drusius. (s) "post potentiores", Junius & Tremellius; "post magnos", Lyra, Cartwright. (t) Misn. Sanhedrin, c. 1. sect. 6.

decline--depart, deviate from the straight path of rectitude.

Thou shalt not follow a multitude to do evil - General usage will never excuse us in any ill practice; nor is the broad way ever the safer for its being crowded. We must inquire what we ought to do, not what the most do; because we must be judged by our master, not our fellow servants; and it is too great a compliment, to be willing to go to hell for company.