9. PREFACE - God wishes that the light shines for all men and that the voices of the Spirits penetrate to all parts so that everyone may obtain proof of immortality. It is with this objective in mind that the Spirits manifest themselves in all parts of the Globe, and that mediumship is revealing itself in people of all ages and all conditions, in men and in women, in children and in old people. This is one of the signs that the predicted times have arrived.
In order to know the things of the visible world and discover the secrets of material Nature, God has given Man bodily vision, the senses and special instruments. With the telescope his eyes reach into the vastness of space; with the microscope he discovers the world of infinite minuteness, and to be able to penetrate the invisible world He has given Man mediumship.
Mediums are interpreters who have undertaken to transmit to mankind the teachings of the Spirits; or rather, they are the material organs of which the Spirits avail themselves so as to be able to express themselves to Man intelligently. They fulfill a sacred mission, seeing that the aim is to open up the horizons of eternal life.
The Spirits come to instruct Man as to his destiny, so that he may be led towards the path of goodness, and not to save him from material work which must be fulfilled in this word for his advancement, nor for the furthering of his ambition and covetousness. This is something which must be clearly understood by mediums so that they will not make bad use of their faculty. Those who fully understand the seriousness of the mandate with which they have been invested will carry out this duty religiously. Their conscience will condemn them if by any sacrilegious act they transform into a distraction or amusement, far themselves or far others, those faculties which were given to them far a serious purpose, which is that of placing them in communication with beings from the other world.
As interpreters for the teachings of the Spirits, mediums should play a very important part in the moral transformation that is in process. The services they are able to offer will be in accordance with the correctness of the orientation they have given to their faculty, because those who follow an incorrect pathway cause more harm than good to the cause of Spiritism. More than one person will delay their progress due to the unfortunate impression these mediums produce. Therefore because of this, all mediums will have to given an account of the use to which they have put their faculty, which was given to them for the purpose of doing good to their fellow creatures.
The medium who desires to be constantly helped by good Spirits will have to work hard towards self-betterment. Those who wish their faculty to grow and be enriched, must therefore enrich themselves morally and abstain from all that can turn them aside from their providential purpose.
If sometimes good Spirits make use of an imperfect medium, it is in order to give good advice, with which they try to make them take the road to goodness. If, however, they meet hardened hearts and their advice is not listened to, they will leave and the field will then be free for the evil Spirits (See chapter 24, items 11 &12(.
Experience has proved that on the part of those who do not take advantage of the advice received from the good Spirits, communications which initially showed some brilliance will, little by little, degenerate and finally fall into error, either in the wording or by becoming ridiculous, which are incontestable signs of the retreat of the good Spirits.
To obtain the assistance of the good Spirits and to remove the lying and frivolous ones, must be the aim to which all serious mediums should join forces and without which mediumship becomes a sterile faculty; even capable of causing detriment to the one who possesses it, since it can become the cause of a dangerous obsession.
Any medium who understands their duty and is not proud of a faculty that does not belong to them, seeing that it may be taken away, will always attribute the good things they receive to God. If their communications receive praise, they will not become vain because they know that these are independent of their personal merit. They will give thanks to God for having allowed the good Spirits to be able to manifest through their intermediary. If there is occasion for criticism, they are never offended because the communications are not their own work. On the contrary, they recognize in their inner selves that they were not able to be good instruments and do not possess all the necessary qualities which would obstruct interference from backward Spirits. Therefore, take care to acquire these qualities and implore, by means of prayer, that your strength does not fail.