Does Biblical law guarantee "free speech"?
When someone says "free speech," they may have in mind one or more things. For example:
- I have the right to publicly express an offensive opinion.
- I have the right to express any fact, even if other people may be offended or experience negative consequences as a result.
- I have the right to express anything I want, including falsehoods, even if other people may be offended or experience negative consequences as a result.
- I have the right to criticize someone in authority, without being penalized by civil government.
- I have the right to say anything I want, without being penalized by any human institution.
- I have the right to lie without consequences.
Therefore, when someone starts talking about "free speech", it will help (both of you) to ask him what he means by "free speech."
Biblical law guarantees you the freedom to say anything which is not expressly prohibited by Biblical law. And Biblical law, being transcendent, is not able to be changed by humans (see Deut. 4:2). In this way, a strict specification of Biblical law is the strongest possible protection of your right to speak any lawful thing you want. [For more information, see How does Biblical law create the strongest possible "Rule of Law"?]
However, Biblical law does not prohibit anyone from taking a range of (lawful) actions in response to your choice to speak. For example, a property owner has the right (under Biblical law) to eject you (using proportional force) from his property if he decides that you are being offensive in some way. A shop owner has the right to refuse to transact business with you (just as you have the same right). Biblical law protects contracts, but does not force anyone to transact business with another person.
The next logical question is: "What speech is prohibited by Biblical law?"
- Idolatrous public worship which might involve speech (Exod. 22:20, Deut. 8:19, Deut. 17:2-5)
- Subornation to idolatry (Deut 13:2-13)
- False prophecy (Deut 13:1-5, Ezek. 13:9, Jer. 14:14, Matt. 7:15)
- Blasphemy (Lev. 24:15-16, Matt. 15:19)
- False witness (Deut. 19:16-20, Matt. 15:19)
- Reviling one's father or mother (Exod. 21:17, Lev. 20:9, Matt. 15:4)
- Reviling a ruler or judge (Exod. 22:28, Acts 23:5)
- Slander (Lev. 19:16, Deut. 22:15-18, Ps. 101:5, Matt. 12:36, Jam. 4:11)
- Fraud (Lev. 19:13, Deut. 25:13-16)
- Lying/false oaths (Lev. 19:12, Matt. 5:37, Eph. 4:25, Col. 3:9, Jam. 3:14)
- Filthy talk (αἰσχρολογίαν: Col. 3:8)
- Boasting (Jam. 3:14, Jam. 4:13-16)
- False teaching (Matt. 15:9, Matt. 16:11-12, Matt. 23:10-22, Tit. 1:9-14, 2 Pet. 2:1-3)
It's important to note that the above list contains a mixture of crimes and (non-criminal) sins. Crimes are sins (transgressions of Biblical law) which have civil penalties explicitly attached (e.g. the death penalty for reviling one's parents). However, if a sin does not have a penalty attached (for example, boasting), then it is not a crime. You are "free" to sinfully boast, in the sense that civil government cannot penalize you for doing so.
Freedom is always limited. "Free speech" is always limited. Throughout history, Christians have either denied or failed to defend and teach the transcendent limits upon human authority encoded in Biblical law. Given such Christian failure, we should not be surprised when our speech is unjustly limited by sinful men who arrogate unjust authority to themselves.