_Rule_ XIX. If in a complex vow or promise there be many things which prove materially unlawful, and one or more that are lawful, the conjunction of the things unlawful doth not disoblige me from the vow of doing the lawful part. Otherwise a man might make void all his vows to God, and oaths and covenants with men, by putting in something that is evil with the good; and so God, and the king, and our neighbours would have their debts paid by our sin and injury done them on the bye. _Rule_ XX. If some part of that which you vowed become impossible, that doth not disoblige you from so much as remaineth possible. As if you vow allegiance to the king, and tyrants or disability hinder you from serving him as subjects in some one particular way, you remain still obliged to serve him by those other ways in which you are yet capable to serve him. So if you had taken an oath against popery, to preach against it, and reject the practice of it, and for ever renounce it; this would not bind you from the common truths and duties of christianity, which papists hold in common with all other christians: nor could you preach against popery, if you were hindered by imprisonment, banishment, or restraint; but you have still power to forbear approving, consenting, subscribing, or practising their errors; and this you are still bound to do. _Rule_ XXI. Though you are not bound to do that of your vow which changes have made impossible or unlawful, yet if another change make them possible and lawful again, your obligation doth return afresh (unless you made it with such limitation). It is not a temporary cessation of the matter, or end, or correlate, that will perpetually discharge you from your vow. If your wife be taken captive many years, when she returneth, you are bound to the duties of a husband. If the king be expelled by usurpers, you are bound at present to so much duty as is possible, and to obey him as your actual governor when he returneth. But in the case of servants and soldiers, and other temporary relations, it is otherwise; for a removal may end the relation itself. If you promise to preach the gospel, to medicate the sick, to relieve the poor, to reform your families, &c. you are not hereby obliged to do it while any unresistible impediment maketh it impossible; but when the hinderance ceaseth, you are obliged to do it again; the matter and your capacity being restored. _Rule_ XXII. Therefore many a vow and promise may be lawfully unperformed, which may not be renounced or disclaimed. When you are taken captives you must forbear your duty to your king, your father, your husband or wife, but you may not therefore renounce them, and say, I have no obligation to them: no, not to the death; because they are relations for life; and how improbable soever it may seem that you should be returned to them, yet God can do it, and you must wait on him.