Withou brotherhood, everything is difficult and unstable

As the reader can verify by referring to the Spirit Magazine of 1862 (a translation by Júlio Abreu Filho, published by Edicel), whose methodical and sequential study has been published in this magazine, Allan Kardec, in answer to a priest who raised the question of miracles, said that Spiritism does not rely on any miraculous fact and, at the end of its explanations, it made known to him a mediumship communication signed by the Spirit of St. Augustine, in which he wrote:

"What doctrine will give more feeling and courage to the heart? Christianity has planted the banner of equality on Earth and Spiritism has raised that of fraternity!... Here is the most heavenly and divine miracle that can happen!... Priests, whose hands are sometimes stained by sacrilege, do not ask for physical miracles , for your brows may break on the stone you trample on to ascend the altar!...
No, Spiritism is not about physical phenomena, it is not based on miracles that speak in the eyes - it gives faith to the heart. Tell me, is not it the greatest miracle there?" (Quoted, pp. 43-46) [The bold is ours.]

The theme of brotherhood is recurrent in Kardec's work, as he made it a point to emphasize, at the same time of the dialogue with the priest mentioned above, when he responded to a New Year message received from the Spirits of Lyon, to whom he said that order, tranquility and the stability of a spirit group require that a brotherly feeling reign in it.

In the same way, the codifier of the Spirit Doctrine used the words "Freedom, Equality, Fraternity" in the analysis of the motto of the French Revolution: three words which, in Kardec's words, constitute in themselves the program of an entire social order which would make the most absolute progress of mankind if the principles they represent could receive full application.
In the article he wrote on the subject, Kardec first recalled that brotherhood, in the strict sense of the word, sums up all the duties of men relative to one another. It means devotion, self-denial, tolerance, benevolence, indulgence; it is the evangelical charity par excellence and the application of the maxim: "To act towards others as we would have others act with us."
It is really easy to understand, the counterpart of brotherhood is selfishness. While the brotherhood says: "Each for all and all for one," says selfishness: "Each one for himself."

Being the negation of each other, it is as unlikely for an egoist to act brotherly toward his fellow men, as it is for a miser to be generous. Now, since egoism is the dominant plague of society, as long as it reigns supreme, the realm of true brotherhood will be impossible; each one will want the fraternity to his advantage, but he will not want it to do it for the benefit of the others.
Considered, therefore, from the point of view of its importance for the realization of social happiness, of the three principles that form the motto of the French revolutionaries, the fraternity is in the first line: it is the base, and without it neither equality nor serious freedom can exist.
Equality, in Kardec's view, stems from fraternity. And freedom is a direct consequence of the other two. The three principles are thus in solidarity with one another and serve each other in support. Without its meeting, the social edifice will not be completed.
One sees, therefore, that brotherly feeling is the key to the stability of both the small group - which are the spirit institutions - and of the larger group, the cities, the nations, the world in which we live.