A liar and a false witness are basically the same; one who says something to another person in order to deceive or mislead that person, or someone who gives their word and fails to keep it. The Bible is filled with verses about not lying, and being honest. We are told: to keep our word letting our yes mean yes and our no mean no (Matt 5:37), that lies defile a man (Mt 15:19-20), and that a lying tongue and a false witness are 2 of the 7 things that are an abomination to God that He hates (Prov 6:16-17,19). (Rev 21:8) goes as far as to say they will have their part in the lake of fire. Let us endeavour to keep our promises and be honest, just as God does (Josh 23:14)(1 Kin 8:56)(Rom 4:20-21).
Some examples of lies:
Saying you will be somewhere at a certain time and not doing so.
Saying you will do some task and not doing it.
Complimenting someone when you don’t mean it.
Exaggerating when repeating a story.
Cheating when doing your income tax returns.
Saying to someone on the phone who you want to get rid of, I have to go because I have work to do outside, then going out and picking up a stick to be “honest.”
In my humble opinion, telling your kids Santa Claus is real and brings presents, or the tooth fairy brings money for losing teeth, is a lie. (See: Q: #183)
Half truths are lies:
You go to the library, then go to a friends house. When you get home, your parents ask where you were and you say, “I went to the library.”
You go shopping and buy five shirts; your spouse asks what did you buy? You hold up a shirt and say, “I bought this shirt,” reasoning that you did buy that shirt, so it is truth.
What the Bible says:
(Col 3:9) Lie not one to another, seeing that you have put off the old man with his deeds;
(Eph 4:25) Wherefore putting away lying, speak every man truth with his neighbour; for we are members one of another.
(Zech 8:16) These are the things that ye shall do; speak ye every man the truth to his neighbour; execute the judgment of truth and peace in your gates:
(Prov 19:5) A false witness shall not be unpunished, and he that speaketh lies shall not escape.
(Prov 12:22) Lying lips are abomination to the Lord: but they that deal truly are his delight.
(Prov 12:17) He that speaketh truth sheweth forth righteousness: but a false witness deceipt.
(Ps 15:1-2) Lord, who shall abide in thy tabernacle? who shall dwell in the holy hill? (2) He that walketh uprightly, and worketh righteousness, and speaketh the truth in his heart.
Keeping your word and not making oaths:
(Mt 5:37) But let your communication be Yea, yea: Nay, nay: for whatsoever is more that these cometh of evil.
(James 5:12) But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and your nay, nay; lest ye fall into condemnation.
(Josh 9:20) This we will do to them; we will let them live, lest wrath be upon us, because of the oath which we sware unto them.
(1 Sam 14:24-26) Saul made a vow that no one should eat until he had full revenge on his enemies. When his son ate honey, God would not reply to Saul’s inquiry of him, because the vow had been broken.