Why did the indians refrain from attacking the english settlers during the first fifteen years of english settlement?

The answer is  They were intimidated by the settlers’ religion
The indians had a lot of respect for religions because it was rooted in their culture to respect those who are already passed.
The indians believed the missionaries that followed the settlers had a good intention from religious point of view and decided to listen to them first.

1621

Explanation:

In the fall of 1621, the Pilgrims celebrated their first successful harvest by firing guns and cannons in Plymouth, Massachusetts. ... While the Wampanoag might have shared food with the Pilgrims during this strained fact-finding mission, they also hunted for food.