We catch our first glimpse of Miriam by the banks of the Nile, covertly watching the floating cradle in which her infant brother Moses lay. While her exact age at this time is unknown, it is commonly supposed that she was a girl still in her teens; yet even here we can see something of that ready wit and innate capacity for leadership which she shared with her two prominent brothers. Noting that Moses had been found by no less a personage than the daughter of the reigning Pharaoh, and that the princess showed willingness to befriend the infant, Miriam came quickly forward. In offering to find someone to care for the child, she concealed the fact that the nurse she had in mind was the baby's own mother, doubtless realizing that their royal benefactress would be disinclined knowingly to entrust Moses to his mother's care, since this renewal of family ties might endanger the plans for adoption which she had already made. (See Exodus 2:1-10.) Miriam's stratagem was satisfactory to all concerned; for, following his training in the home of his parents, Moses entered the palace, and became "learned in all the wisdom of the Egyptians" (Acts 7:22).
The second scene in Miriam's career, as outlined in the Bible, represents her as fulfilling the promise of her girlhood and leading the women of Israel in a song of joyous gratitude for the safe passage of the Red Sea and for the downfall of the Egyptians (Exodus 15:20,21). Here she is described as "the prophetess," and it is suggested that she further expressed her gladness on this occasion by dancing to the sound of a timbrel. In those early days the work of prophecy was not seldom accompanied by music and dancing. David himself "danced before the Lord" when the ark of the covenant was brought to Jerusalem (II Samuel 6: 14); while he appointed men to "prophesy with harps, with psalteries, and with cymbals" (I Chronicles 25:1). Such musical interludes were regarded as symptomatic of joyous religious fervor.
The twelfth chapter of Numbers records an incident in the colorful life of Miriam which is as unfortunate as it is revealing. We find her criticizing her famed brother Moses and belittling his importance because "he had married an Ethiopian woman." The ultimate causes of this outburst are not expressly revealed, but the record at least makes plain that her criticism of Moses and doubts of his leadership brought upon her the dread disease of leprosy (verse 10). However, thanks to the selfless prayers of Moses, she was healed forthwith.