A First Century Christian Writing called the Didache, or Teaching of the Twelve Apostles, one of the First Post-Biblical writings, explicitly condemns abortion, and says the Lord and Apostles handed this down. Many Biblical texts do so also.
"The Didache
solemnly states, as
Priests for Life, led by Fr. Frank Pavone, notes:
The Lord’s Teaching to the Heathen by the Twelve Apostles … The second commandment of the Teaching: “Do not murder; do not commit adultery”; do not corrupt boys; do not fornicate; “do not steal”; do not practice magic; do not go in for sorcery; do not murder a child by abortion or kill a newborn infant.” For “this is the way of life” while “[t]here are two ways, one of life and one of death; and between the two ways there is a great difference,” and the way of death leads to a culture of death and to perdition if unrepented.
It is neglect of the sovereign divine commandment “Thou shalt not kill” (Ex. 20:13), enshrined in the Law given to Moses, and still earlier in the precepts of natural law confirmed to Noah: “Whosoever shall shed man’s blood, his blood shall be shed: for man was made to the image of God” (Gen. 9:6), that has led to the greatest and most tragic genocidal holocaust of our time, of nearly 2 billion children cruelly killed worldwide."
https://onepeterfive.com/evil-abortion/