Blood kinship is not necessarily spiritual kinship. The body arises from the body, but the spirit doesn't arise from the spirit, for the spirit existed before the body was created. It is not the father who creates the spirit of his son, he only gives him the physical sheath, but he must help him to develop intellectually and morally so that he may progress.

The spirits who incarnate in the same family, especially as close relatives, are generally sympathetic spirits, united by previous relations expressed by affection during the earthly life; but it may also happen that these spirits are complete strangers to each other, separated by previous antipathies, which are expressed in the same way by their opposition on earth to serve as a test for them. The real family ties are therefore not those of consanguinity, but those of sympathy and agreement of thought, which unite the spirits before, during and after their incarnation. It follows that two beings born of different parents may be closer brothers by spirit than they would be by blood. They can attract, seek and please each other, while two brothers related by blood can repel each other, as we experience daily; a moral problem that only spiritism can solve through the plurality of existences.

Así pues, hay dos tipos de familia: la familia a través de los vínculos espirituales y la familia a través de los vínculos físicos. La primera es permanente, se fortalece mediante la purificación y se perpetúa en el mundo espiritual a través de los diversos vagabundeos del alma. El segundo, tan frágil como la materia, se extingue con el tiempo y muy a menudo se disuelve moralmente, incluso en la vida presente. Jesús quiso dejarlo claro al decir a sus discípulos: „Aquí están mi madre y mis hermanos, es decir, mi familia por los vínculos espirituales, pues todo el que cumple la voluntad de mi Padre que está en los cielos es mi hermano, mi hermana y mi madre.»

The hostility of His brothers and sisters is clearly shown in the account of the apostle Mark, for he says that they sought to seize Him on the pretext that He was beside Himself. At the announcement of His coming, and knowing their feelings towards Him, it was natural for Him to say from a spiritual point of view concerning His disciples, «These are My true brothers and sisters». Although His mother accompanied them, He generalised the teaching, which in no way meant that He intended to say that His physical mother meant nothing to Him as a spirit and was indifferent to Him. His behaviour on other occasions sufficiently proved the contrary.