Jesus said: “Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform your oaths to the Lord’. But I say to you, do not swear at all: neither by heaven, for it is God’s throne; nor by the earth, for it is His footstool; nor by Jerusalem, for it is the city of the great King. Nor shall you swear by your head, because you cannot make one hair white or black. But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No’. For whatever is more than these is from the evil one” (Matthew 5:33-37 - NKJV), and James confirmed His words saying: “But above all, my brethren, do not swear, either by heaven or by earth or with any other oath. But let your ‘Yes’ be ‘Yes,’ and your ‘No,’ ‘No,’ lest you fall into judgement” (James 5:12 – NKJV).

Therefore, as believers, we cannot swear any kind of oath, lest we fall into the judgement of God. Thus, if we are called to testify in court, we cannot swear to tell the truth. We simply tell the truth, for God commands us to speak truthfully to everyone.