As a Christian it is wrong to swear upon the Bible in court?
There are two passages in scripture that are relevant to this question for the New Testament believer.
The first is found in Matthew 5:
“33 “Again, you have heard that the ancients were told, ‘You shall not make false vows, but shall fulfill your vows to the Lord.’ 34 But I say to you, make no oath at all, either by heaven, for it is the throne of God, 35 or by the earth, for it is the footstool of His feet, or by Jerusalem, for it is the city of the great King. 36 Nor shall you make an oath by your head, for you cannot make one hair white or black. 37 But let your statement be, ‘Yes, yes’ or ‘No, no’; anything beyond these is of evil.”
The second is in James 5:
“12 But above all, my brethren, do not swear, either by heaven or by earth or with any other oath; but your yes is to be yes, and your no, no, so that you may not fall under judgment.”
James is clearly echoing Jesus’ words. The Bible teaches Christians should not take oaths. However, the context of these passages helps clarify for us under what circumstances oath-taking is wrong.
In Matthew 23, Jesus pronounces eight “woes” on the scribes and Pharisees. Woes are effectively curses, condemnations to Hell. This is extremely serious, because Jesus, who is God, is telling the scribes and Pharisees they are condemned. Once God pronounces this, it is forever done. One particular woe has to do with oaths:
“16 “Woe to you, blind guides, who say, ‘Whoever swears by the temple, that is nothing; but whoever swears by the gold of the temple is obligated.’ 17 You fools and blind men! Which is more important, the gold or the temple that sanctified the gold? 18 And, ‘Whoever swears by the altar, that is nothing, but whoever swears by the offering on it, he is obligated.’ 19 You blind men, which is more important, the offering, or the altar that sanctifies the offering? 20 Therefore, whoever swears by the altar, swears both by the altar and by everything on it. 21 And whoever swears by the temple, swears both by the temple and by Him who dwells within it. 22 And whoever swears by heaven, swears both by the throne of God and by Him who sits upon it.”
The scribes and Pharisees were making oaths they did not intend to keep while ignoring other oaths when it suited them. For example, they may swear “by the temple," but they had no intention of honoring their oath, making an excuse that one only had to honor an oath sworn by the “gold of the temple."
In other words, these hypocrites found a convenient excuse to lie or renege on a promise whenever they wished. For this, Jesus condemns them. He points out the gold of the temple is not more important than the temple that sanctifies the gold. Their excuses for breaking promises were based on contrived technicalities that didn't even make logical sense.
Based on the context of these passages, we can understand why taking oaths voluntarily is a sin. A person taking a voluntary oath is attempting to convince someone else they are telling the truth. Phrases like “I swear on a stack of Bibles” or “I swear to God” are given as evidence someone is not lying, which is only necessary when the person is suspected of being untrustworthy. Therefore, when a person volunteers to take an oath, they usual do so to compensate for lack of trustworthiness.
This is the context in which Jesus condemns oath-taking in Matthew 5. Notice the first verse: “Again, you have heard that the ancients were told, ‘You shall not make false vows, but shall fulfill your vows to the Lord.'” Jesus condemns hypocrisy and challenges the idea of oaths compensating for untrustworthiness. Jesus says a righteous man should not swear by anything, because his yes will be yes, and his no will be no. In other words, trustworthy individuals don't need to resort to taking oaths.
Therefore, a Christian should be trustworthy in everything he or she says and does, thereby making oaths unnecessary. Jesus says Christians are not to make voluntary vows to enhance our promises, for doing so suggests we are less than trustworthy under normal circumstances.
Furthermore, the habit of making vows creates a temptation for legalism and hypocrisy, since we establish our promise under a technical constraint that we can manipulate to fit our desires (like a child who crosses his fingers while making a promise).
The Bible teaches that our honesty and integrity must be of the most importance. When we say we are going to do something, we should honor our word. James stresses the importance of demonstrating our faith by our works (chapter 2), and living up to our word is a work of our faith. Taking oaths doesn't improve a Christian's witness; it just complicates it.
Therefore, Christians are not to make voluntary oaths as a means of enhancing our trustworthiness. Instead, we display trustworthiness in everything we say and do, thus negating the need for oaths.
On the other hand, we may encounter situations in civil society when we are required to take an oath (e.g., in a court of law, entering the military, etc.). In these cases, the oath we take is not voluntary, which changes the situation significantly. Voluntary oaths are taken to enhance personal credibility, which Jesus says is a sinful crutch, but involuntary oaths serve an entirely different purpose.
Involuntary oaths are required as a matter of law to notify a person taking an oath they are subject to perjury penalties. This oath is not a guarantee of trustworthiness; it merely establishes legal authority to hold a person accountable for dishonesty. So a Christian may freely take an oath when required by law since this is not a voluntary act intended to compensate for untrustworthiness.
In fact, when a Christian agrees to take an official oath as required by law, he or she is displaying respect for authority and law, which is consistent with trustworthiness. Conversely, a refusal to take a required oath would suggest less trustworthiness, which is not the witness a Christian should seek.
Finally, the manner of taking an oath may be of concern to some Christians. For example, the tradition in many courts is to use a Bible in the oath-taking process, but in light of Jesus' words in Matthew 5, some Christians may object to this practice. Under these circumstances, courts allow a person to swear an oath without the use of a Bible. In all cases, let your conscience be your guide, doing your best to balance your witness and your desire to obey the law.