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.

In Genesis 34:30, this signifies abhorrence from people who were of the Ancient Church. (Arcana Coelestia 4516)

In Exodus 7:21, this signifies aversion from truth falsified or from mere memory-knowledges of truths. (Arcana Coelestia 7319)

To 'stink,' as in Genesis 34:30, denotes aversion and abomination.