What does what is the nature of this covenant mean in the question

Breaking down "nature of this covenant"...

Nature refers to the characteristics of the covenant

A covenant is an agreement, sort of like an informal contract

While you didn't provide us with Chapter 19, versus 5 and 6, reading the rest of the question it can be inferred God is telling the Israelites to "keep his covenant."

To answer the question "What is the nature of this covenant?" read the chapter and ask yourself the following questions:

Is God stern with the Israelites? Helpful? Angry? Happy? Does He feel bad for them? Does He take pity on them? Are they loyal to God?

Does God get more out of the covenant than the Israelites do? Who does the covenant benefit more?

How do the Israelites feel about the covenant? How do they feel about their current situation in general? Does the convenant calm them? Inspire them?

affirmative action refers to the policies that take gender, race, or ethnicity into account in order to promote equal opportunity.

employers subject to title vii are prohibited from taking race or sex into account in any employment decisions. aa is a penalty for having any job group substantially statistically "underutilized" in any race or either sex. the employer must take steps to eliminate the underutilization, then stop, ending its aa efforts

a drastic rise in oil prices ended decades of postwar.