Three
The number three in the Bible represents completeness. That's why Jesus rose on the third day after the Crucifixion -- his transformation was complete. It's why Elijah stretched himself on the dead child three times, why Jonah was in the belly of the fish for three days, why the Lord called Samuel three times, and many more. It's also reflected in the fact that there are three levels of heaven, three levels of hell, three levels to human life and, ultimately, three aspects of the Lord Himself: Father, Son and Holy Spirit.
Arcana Coelestia # 7382
7382. 'Stretch out your hand with your rod' means the power of inward truth directed through outward truth. This is clear from the meaning of 'hand' as spiritual power, which belongs to inward truth, and from the representation of 'rod' as natural power, which belongs to outward truth, both dealt with in 6947, 6948. For the fact that all power in the spiritual world belongs to truth, see 3091, 3787, 4931, 6344, 6423, 6948. Since 'Moses' represents inward law, which is the same as inward truth, and 'Aaron' represents outward law, which is the same as outward truth, and since inward truth flows into outward truth and gives it power, 7381, Moses' word of command to Aaron 'stretch out your hand with your rod' means the power of inward truth directed through outward truth.