What do we do when faith fails? When we mess up and fail, how can we recover from that place? Abram failed also. He lost faith and behaved in a truly selfish way toward his wife, valuing his own skin above her purity. He was willing to lie, and even sell off his wife, to save his own life.
But then, after he is caught, he comes to sincere and genuine repentance. He returns to the place of his first altar, when he first called upon the Name. This is our example. We can always repent, no matter how fare we have strayed.