Mandatory vaccinations are against biblical principles. The government doesn't have the right to mandate any medical procedure. Every person has authority over his body (8th commandment) and every Christian must do with his body which isn't in violation of a clear conscience before God (Rom. 14:23; 1 Cor. 6:19-20).

See a more expanded explanation here: https://gereformeerd.org/wp-content/uploads/2021/09/Vaccines-Biblical-Argument-against-Mandating-Vaccines.pdf