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?

he would based it upon geographic luck which he often resulted his faith in.

the underground railroad (apocope of the metropolitan railroad) is a system of urban trains located within a city and its metropolitan area. it is characterized for being a massive transport of passengers in the big cities, uniting diverse zones and their environs, with high capacity and frequency and in segregated form to other systems of transport. metropolitan railroads are built underground or on the surface, although most systems use mixed models where sections are combined in both modalities.

1 - as a result, the metro tends to reduce car travel for two reasons: first, due to the greater transfer of users from the car and, second, due to the reduction in the acquisition of cars in homes located in sectors near the stations of the metro.

2 -the metro allows to contribute effectively to the achievement of all the objectives of an urban development policy: it improves the efficiency of the city's economy by reducing travel costs and also generates a higher level of activities in the city center, taking advantage of of the agglomeration economies.

3 -it is a clean means of transport, since it uses renewable energy (usually electricity), taking care of the environment and avoiding excessive pollution.