God makes multiple covenants with Abram. We can think of it as one covenant with multiple parts. Like different articles of the Constitution.
Abram had already been declared righteous in God’s sight solely by faith. That statement had no remaining conditions.
This provision in chapter 17 is different. It is mutual. God has a role and Abram has a role. What God does will depend on what Abram does. Abram’s part is to live faithfully, righteously. “Blameless.” If Abram does this, then God’s part is to reward Abram with additional blessings, to multiply him “exceedingly”.
God had already promised unconditionally to make Abram’s descendants as the stars of heaven. So ”multiply exceedingly” must extend beyond mere numbers. And of course it did. God will later grant that Jesus, the deliverer of Israel and eternal king of the earth comes from the seed of Abram. And the Bible declares that Abram is the father of all who believe.
From these various provisions we learn that God’s acceptance is unconditionally given. And when He grants a reward or gives a gift, it is irrevocable. We can possess these gifts and still have amazing future rewards connected with our current choices. Rewards continue to accumulate if we continue to walk in obedience.
God calls us to be people who walk in faith now to sow seeds that bless future generations. Like Abram. We can take from Abram that when we exert effort to walk in faith, God blesses it beyond what we can imagine. However, no matter how well we might do, or how many rewards we might accumulate along the way, there is always more to strive for. Some of Abram’s greatest tests still lie ahead.