I read in the New Testament Student institute manual: “Tradition indicates that John may have been Jesus’s first cousin. This tradition also indicates that Salome, who is mentioned in Mark 16:1, was the sister of Jesus’s mother, Mary, and the mother of James and John.” I’m confused as to how this assumption that Mary (the mother of Jesus) and Salome is being made and what tradition they are referring to. Perhaps the association of Salome and Mary at several key events?
There are two questions you are asking. The first is how the student institute manual is drawing the conclusion that Mary (mother of Jesus) and Salome were sisters. The second question is asking to know what tradition they are speaking of. Let’s begin with your first question by reviewing the verses that correlate who Salome is. (Keep in mind this is NOT the Salome that requested the head of John the Baptist.) Here are the following verses of scripture that help identify the relationship:
Mark 16:1 we read,
“And when the sabbath was past, Mary Magdalene, and Mary the mother of James, and Salome, had bought sweet spices, that they might come and anoint him.”
“There were also women looking on afar off: among whom was Mary Magdalene, and Mary the mother of James the less and of Joses, and Salome;”
“And many women were there beholding afar off, which followed Jesus from Galilee, ministering unto him:
Among which was Mary Magdalene, and Mary the mother of James and Joses, and the mother of Zebedee’s children.”
In each verse of scripture we can recognize that three women are always mentioned: Mary Magdalene, Mary (mother of James and Joses), and Salome (who is wife to Zebedee and the mother of James and John). These verses are highlighting family relations between these women.
As to your second question, the student manual highlights the tradition of bringing spices to a burial in New Testament times. The tradition of bringing spices during a burial was accomplished by family members. In that light, the student manual is giving evidence that Salome (the mother of James and John) is probably the sister of Mary (mother of Jesus), because she is specified as one of the three women who came to Christ’s tomb — with spices — in order to anoint his body. Spices were used to anoint the body in order to remove the odor that happens when corpses decompose.
From the following Jewish Encyclopedia we can read the following statement,
“Throwing Earth Upon a Coffin.(From Picart, 1723.) As soon as the last breath was drawn, the eyes of the dead were closed by the oldest or the most distinguished son or next relative (Gen. xlvi. 4), the mouth was shut, and kept in position by a band on the cheek-bones, and the body placed upon sand or salt on the floor to retard decomposition, metal or glass being put upon the navel to prevent swelling. Then the body was washed and anointed with aromatic unguents, and wrapped in linen clothes (Shab. xxiii. 5; Sem. i. 2, 3; Acts ix. 37; John xi. 44, xii. 7, xix. 39 et seq., xx. 6 et seq.; Matt. xxvii. 59; Mark xv. 46 et seq.; Luke xxiii. 53 et seq.; Testament of Abraham, xx.). (emphasis mine)
As these traditions were performed by family members the manual is drawing the correlation between the burial, who was visiting the burial tomb, and what they were there to do.