1 Now Adam knew Eve his wife, and she conceived and bore Cain, saying, “I have gotten a man with the help of the Lord.”
2 And again, she bore his brother Abel. Now Abel was a keeper of sheep, and Cain a worker of the ground.
The relationship between God and the first two people is clearly a close one. The two brief verses for today also indicate the trust level that Eve had in God's promise. He told her that from her would come someone who would be able to redeem them from the sin that they had invited into their lives. As soon as Cain is born, she believes the promise has been fulfilled. "I have gotten a man with the help of The Lord." She assumed the promised one was here. You have to admire her faith.
She was of course wrong. The Savior doesn't come upon the scene for several thousand years. But here we see that she has faith that God will keep that promise and she is counting on it. When Abel comes along, she is confused. If the promised one is here, why do we need another? Obviously, Eve did not understand the entire plan. Fortunately for us, we don't have to understand God entire plan in order to receive the benefits of His blessings. Eve didn't have to understand the details of God's plan of salvation from the mess she made. She needed to believe that He would take care of it. God didn't owe her an explanation of just how the whole Savior thing was going to take place. Her faith was in God, not the details of the plan.
So often we demand explanations from God and that is the basest hubris. God owes us no explanations. He made numerous promises throughout Scripture with Genesis 3:15 just being the first. Every single one of those promises was or will be kept - even the sending of the Savior. We can believe right along with Eve even if we don't understand it all.