)explain governor john winthrop’s legal and biblical justification for for seizing indian land.

It did not matter to John Winthrop or his system much that natives were on that land because the bible did not speak of creating those people so according to god they should not even be people, which opens up the way for the colonists to take their land since they were  the "sons of adam" while the natives were savages. This was a common sentiment during the puritan era.