When I go to court as a witness, I affirm rather than swear on the Bible. This is because I am a Christian and the Bible is clear on this point, in the Epistle of St James which states: “Swear not, neither by heaven, neither by the earth, neither by any other oath.”
George Fox, the founding Quaker, took this seriously and landed in prison several times, nearly costing him his life. He wrote a fine passage in his journals describing his trial in 1663, in which he refused to take his hat off, rebuked the judge for calling him “sirrah” and, when asked if he would take an oath, replied: “Christ, who is the great prophet, who is the King of kings, who is the Saviour of the world, and the great judge of the whole world, he saith I must not swear; now, whether must I obey, Christ or thee?”
Today, when objectors to oaths may affirm, the main dispute is between believers who want the oath retained and secularists who want it abolished, which is quite a paradox really!