By this point God had already made his single-sided covenant with Abram. Abram slept through the whole thing while God made the commitment. In this chapter, God institutes the practice of circumcision for Abram and his family, and for what will become his chosen nation, Israel. Also, because during Bible times names were so important, God changes Abram’s name to ‘Abraham’ meaning ‘father of many’. This was another promise that God would fulfil what he had prophesied. This has in fact come true because not only do Jews and Muslims trace their heritage back to Abraham, but so also do Christians who are considered to be the spiritual children of Abraham.
As for the land that God promised, the title deeds are unconditional, that land belongs to the Jews – but that’s not to say that they couldn’t be removed from it from time to time as they rebelled against God. This has happened, and now they are in the process of returning to it for the final time (as we see from Ezekiel).
Circumcision was instituted as a symbol of belonging – it didn’t say anything about a person’s salvation, it merely was a symbol of the parents’ obedience.