Thou shalt not bear false {m} witness against thy neighbour.

(m) But further his good name, and speak truth.

Wesley's Notes

20:16 Thou shalt not bear false witness - This forbids, Speaking falsely in any matter, lying, equivocating, and any way devising and designing to deceive our neighbour. Speaking unjustly against our neighbour, to the prejudice of his reputation; And (which is the highest offence of both these kinds put together) Bearing false witness against him, laying to his charge things that he knows not, either upon oath, by which the third commandment, the sixth or eighth, as well as this, are broken, or in common converse, slandering, backbiting, tale - bearing, aggravating what is done amiss, and any way endeavouring to raise our own reputation upon the ruin of our neighbor's.

Matthew Henry's Concise Commentary

20:12-17 The laws of the SECOND table, that is, the last six of the ten commandments, state our duty to ourselves and to one another, and explain the great commandment, Thou shalt love thy neighbour as thyself, Lu 10:27. Godliness and honesty must go together. The fifth commandment concerns the duties we owe to our relations. Honour thy father and thy mother, includes esteem of them, shown in our conduct; obedience to their lawful commands; come when they call you, go where they send you, do what they bid you, refrain from what they forbid you; and this, as children, cheerfully, and from a principle of love. Also submission to their counsels and corrections. Endeavouring, in every thing, to comfort parents, and to make their old age easy; maintaining them if they need support, which our Saviour makes to be particularly intended in this commandment, Mt 15:4-6. Careful observers have noted a peculiar blessing in temporal things on obedient, and the reverse on disobedient children. The sixth commandment requires that we regard the life and the safety of others as we do our own. Magistrates and their officers, and witnesses testifying the truth, do not break this command. Self-defence is lawful; but much which is not deemed murder by the laws of man, is such before God. Furious passions, stirred up by anger or by drunkenness, are no excuse: more guilty is murder in duels, which is a horrible effect of a haughty, revengeful spirit. All fighting, whether for wages, for renown, or out of anger and malice, breaks this command, and the bloodshed therein is murder. To tempt men to vice and crimes which shorten life, may be included. Misconduct, such as may break the heart, or shorten the lives of parents, wives, or other relatives, is a breach of this command. This command forbids all envy, malice, hatred, or anger, all provoking or insulting language. The destruction of our own lives is here forbidden. This commandment requires a spirit of kindness, longsuffering, and forgiveness. The seventh commandment concerns chastity. We should be as much afraid of that which defiles the body, as of that which destroys it. Whatever tends to pollute the imagination, or to raise the passions, falls under this law, as impure pictures, books, conversation, or any other like matters. The eighth commandment is the law of love as it respects the property of others. The portion of worldly things allotted us, as far as it is obtained in an honest way, is the bread which God hath given us; for that we ought to be thankful, to be contented with it, and, in the use of lawful means, to trust Providence for the future. Imposing upon the ignorance, easiness, or necessity of others, and many other things, break God's law, though scarcely blamed in society. Plunderers of kingdoms though above human justice, will be included in this sentence. Defrauding the public, contracting debts without prospect of paying them, or evading payment of just debts, extravagance, all living upon charity when not needful, all squeezing the poor in their wages; these, and such things, break this command; which requires industry, frugality, and content, and to do to others, about worldly property, as we would they should do to us. The ninth commandment concerns our own and our neighbour's good name. This forbids speaking falsely on any matter, lying, equivocating, and any way devising or designing to deceive our neighbour. Speaking unjustly against our neighbour, to hurt his reputation. Bearing false witness against him, or in common conversation slandering, backbiting, and tale-bearing; making what is done amiss, worse than it is, and in any way endeavouring to raise our reputation upon the ruin of our neighbour's. How much this command is every day broken among persons of all ranks! The tenth commandment strikes at the root; Thou shalt not covet. The others forbid all desire of doing what will be an injury to our neighbour; this forbids all wrong desire of having what will gratify ourselves.