The sanctity of life is a basic moral concept. The Bible is not going to address abortion...first off they would have called it killing, not have come up with a rosy politically correct word for it. Instead of killing, they are into bloodlines and producing children. There is not a lot of the blood thirsties running around wanting to kill babies. If some one was promoting that they would have had the good sense to burn them at the stake because that can only come from Satan. So Christ is not going to address abortion directly.
Then there are other things that the Bible did not address that the Holy Spirit taught Christianity after the close of the Bible. It is true that....
Christ nor the NT, did not denounce slavery.
Christ nor the NT, did not denounce polygamy.
Christ nor the NT, did not address concubinage.
Christ nor the NT, did not address men marrying girls in their early teens.
Christ nor the NT, did not campaign for women's rights.
Christ nor the NT, did not address fathers choosing their daughter's husbands.
Christ nor the NT, did not require marriage ceremonies.
It took Christianity a long time to value Freedom and Liberty.
As time went on the Holy Spirit taught us additional moral values. So as a person that believes in the "Living Word of God" this is no mystery to me. 2000 years and the Living Word of God still has things to teach us. The people that are going to have the most problem with this are those that think that the Bible defined all aspects and beliefs of Christianity. That the Holy Bible is the final word for Christianity. That is not true, the Holy Spirit taught us many things after the close of the Bible. This was one of the functions of the Holy Spirit that Christ told us about.