Zechariah 8:17
And let none of you imagine evil in your hearts against his neighbour; and love no false oath: for all these are things that I hate, saith the LORD. And let none of you imagine evil in your hearts against his neighbour; and love no false oath: for all these are things that I hate, saith the LORD.
The command forbids imagining or devising evil in the heart against a neighbor, and that inward imagining includes both thinking evil and speaking evil against others. It declares these to be things the Lord hates, both the imagining of evil against a neighbor and the loving of a false oath. These evils, together with selfishness and double dealing, corrupt the soul temple, while contention and dissension are not from God but are fruit of the wild olive tree.
Through such sins the Jewish nation lost its freedom, and God could not protect them while they turned away from doing His will. The evil is especially to be guarded against among believers, for to speak falsely against Christ's followers is to repeat the reproach borne by Christ, who was without sin, and to treat them as the Jewish nation treated the Redeemer. Applied among believers, the prohibition forbids suspicion, backbiting, and false accusations against fellow workers.
Among fellow workers it means refusing suspicion, prejudice, jealousy, and hostile reports about one another, and instead being faithful, frank, and true to one another's interests. Harboring suspicion and evil surmising against fellow believers violates this command and can alienate people who should be serving God. God's people are to put the Bible's teachings into practice by refusing to speak or think evil against others.