Why is the second day of creation different than all the others? In reading Genesis 1, is there something special about the second day?
In a negative sense, there is something significant about this day. God leaves something out that happens on every other day. The passage says:
And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so. And God called the firmament Heaven. And the evening and the morning were the second day. (Gen 1:6-8)
Think back to the account of creation. On every other day God "said" and God "saw." The first time each day God said, "Let there be." You see it in the passage above. But where is the "and God saw?" It's not there. There is a "God made" and a "God called," but not a "God saw." What was it God saw on all other days that He didn't see here? On every other day he saw that His work that day was good. The second day was not good.
This may be a strange thought to some. How could God do something that even He could not call good? And yet, here it stands out, because it is formulaic on all other days, that God created and didn't call it a good day.
On day two God created the "firmament," the expanse of the skies. There is nothing in that that seems to be less than good. But what did God do with that firmament? He used it to divide the waters from the waters. This is the first time that division came into the world. Granted that in the verses just previous God divided the light and the darkness (and the Hebrew word is the same). In that instance, though, He divided two different essences—light and dark, good and bad, righteousness and sin. In day two he divided the waters from the waters, the same essence. And He could not call that day good, because God does not like division.
Nothing has changed. God still doesn't like division.
He doesn't like anyone to cause division in marriage. Jesus says that God hated this division from the beginning. "They say unto him, Why did Moses then command to give a writing of divorcement, and to put her away? He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so."
God doesn't like anyone to cause division in His church. "Now I beseech you, brethren, by the name of our Lord Jesus Christ, that ye all speak the same thing, and that there be no divisions among you." (1 Cor 1:10) God intended for there to be "one body" (Eph 6:4), and severe measures are to be taken to preserve it. "Mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them." (Rom 16:17)
More than anything, though, God hates that which separates between his creation and Himself—sin (Isa 59:2). Maybe this, more than anything else, is why he did not call the work of day two good. We are made in the image of God (Gen 1:27) and have the breath of God in us (Gen 2:7). We are of the same essence as God, as the waters above and below the firmament were of the same essence. When we depart from God, he uses the picture of divorce (Jer 3:1-2; Hos 2:2) to portray his disappointment. He hates being separated from us in the same way he hates divorce. Perhaps that explains the extreme measure of sending his son to die, so that we might be reconciled.
On day two of creation, God did not have a good day. Let's not make it any worse for him. Let us work so that the division of the waters is the only division God has to worry about.