Give God the Glory in It
Abortion is never ok. If someone is willing to reject life literally (in the natural), then that same root in the heart will lead to rejecting the supernatural...therefore leading to all sorts of ways of thinking, compromising, rejecting the Holy Spirit (like the Pharisees and Romans did with Jesus - rejecting the natural (they killed Jesus literally); and the supernatural - they refused to hear what the Spirit of God was saying through His own Son who represented God in the flesh).
God is very clear (Deut. 30:15, 19). God is for life because He is Life and He is the Creator of life. This is nothing but a root of rejection that causes one to commit such an act (as like the example of Jezebel in 1Kings 17-22). If you have not gotten rid of the root of rejection, than at one point it will and can cause one to reject someone else's life and even if they are a Christian...possibly one of their own brethren and Christ Himself (the Spirit of God)...pretty scary! Afterall, isn't one's life part of their inheritance, and isn't this what Jezebel stole from Naboth...an inheritance (it was his land, one of many blessings from God, or an inheritance like children are [Ps. 127:3; Ps. 139:13-16; John 16:21; Ps. 127:1-5; Mark 10:14; Isa. 8:18]?
The Lord can forgive those that have committed this act, but it's also important to seek deliverance of the root that caused it in one's heart (and this also entails those that are Christians that are willing to compromise on this issue...as it's not just an 'issue' to God the Father, but a life which is very important to Him). The world will say that there are circumstances that may be alright (rape...life at risk, etc.) but isn't this a lack of trust in God Almighty? There is a purpose for everything. For the one raped...He could create a child of God through that terrible incident that will save many lives, when the child grows up...and the one raped could be delivered by Jesus' saving Power of the Holy Spirit and become a testimony to those that have also gone through similar experiences. The one that has life threatening issues...perhaps the Lord may save the life in an impossible situation or may take one life to save many (sounds like the act of the cross, hugh?). There are many ways God's work can be portrayed in these matters, where the Lord gets the glory and no man, nor no works of the enemy...just God Almighty. Isn't this what we are all called to do...give God the glory in all things (1 Cor. 6:19-20)?
What a way to testify of Himself. We never know what God can do with a situation, unless we allow Him to be God, and reveal to us His love. More than likely when others fall into this trap of the enemy (Matt. 13:24-28, this is darnel that has crept in); allowing one to think there is a reason to end someone else's life by their own doing, than it's probably because they have not had the chance to experience the true Power of God...that same Power of God that overcame death on the cross...Jesus Christ (1Cor. 1:24).
God is all powerful and He deserves to portray it through any life He chooses and however He chooses (Ps. 115:3).
Other Scriptures to remember in pondering all this: John 10:10; 1 Pet. 5:8; John 15:18; 2 Cor. 12:9; 1 John 1:1-10; 1 Cor. 2:14
To God the Father in heaven and His Son Jesus be the glory!