What happened to the mixed multitude? Like the Israelites, they fell in the desert, leaving their offspring to find rest in the Promised Land. Two men survived the desert. One was the Israelite Joshua – The Lord's salvation - a type of Jesus. The other was Caleb – the faithful, wholehearted one - an example for us.
Scholars say Caleb was an outsider, a part of the mixed multitude. Like us, he was adopted into God's family. God rewarded Caleb for choosing faithfulness and righteousness over comfort and pleasure.
Some offspring of the mixed multitude became the Rechabites. They set themselves apart by faithfully following laws God placed in their hearts.
The mixed multitude that would not be set apart for God's glory were set apart from (or excluded from) God's glory.
The flesh hates discipline and will try to shorten or avoid it. The Spirit loves training and leads God's warriors into it because the end result is the fruit of righteousness for the glory of God.