We need our great king, to make a judicial pronouncement – that our sins have been dealt with at the cross, and that our souls have been dressed with his righteousness.
Do you see God’s grace? By entering into a covenant with us – and making solemn promises, and giving visible signs, God is bending over backwards to us to prove his trustworthiness and goodness.
As you see the confirmations God gave Abram, you can humbly thank God, that he himself has confirmed, by his own power, by his own promise, by his own covenant – He is committed to deliver his blessings to you.