What does Mark 14:59 mean?

In the Mosaic law, a conviction requires two witnesses (Deuteronomy 19:15). There is only one crime in which only one witness is necessary, and that is the rape of a woman where her cries for help cannot be heard (Deuteronomy 22:25–27). The Sanhedrin is trying to find people willing to testify they witnessed Jesus committing a crime. Several things are wrong with this.

First, properly-functioning authority does not arrest someone first, then try to figure out what crime they committed. Righteous leaders only arrest someone because they highly suspect that person committed a specific crime. In this case, the Sanhedrin has long-since decided they want Jesus dead (John 11:48–53). All they are doing here is fishing for a justification.

Second, Jesus has not, in fact, broken actual Mosaic law, nor the civil laws put in place by the Romans. Literally speaking, there's nothing to charge Him with. So the Sanhedrin court seeks people who will lie (Matthew 26:59), which is itself a capital crime in the Mosaic law (Deuteronomy 19:18–19).

Third, it's hard to find people who can tell the same lie without a great amount of corroboration. For capital crimes, two or more witnesses must have the same testimony, but none of the witnesses' stories match.

Some witnesses have come forward to claim Jesus said He was going to destroy the temple (Mark 14:58). This is a useful accusation, since destroying a religious facility is against Roman law. But even members of the Sanhedrin know that Jesus didn't say that He, personally, would tear down the temple (John 2:19–21). Some, at least, also understand He was referring to His body, not the building (Matthew 27:62–64; 28:11–15).

As of the writing of this commentary, this passage is incredibly applicable to modern times. The Sanhedrin are actively seeking fake evidence to support their political goals. We may be tempted to read this two thousand years later and shake our heads at their arrogance and duplicity…but our culture does the same, and so do some of us, personally. "Fake news," partial information, rumors, misleading headlines, and so forth are rampant. This is especially true on the internet. This deceit is carefully cultivated to reinforce whatever someone wants others to believe.

God values truth, not lies. Consider that false accusations are punishable by death in the Mosaic law. We must be careful about what we believe, what we read, and what we pass on to others. Our carelessness and pride may not literally cause the death of an innocent man; then again, it might.