CCC 2260 The covenant between God and mankind is interwoven with reminders of God’s gift of human life and man’s murderous violence:
For your lifeblood I will surely require a reckoning. .. Whoever sheds the blood of man, by man shall his blood be shed; for God made man in his own image.1
The Old Testament always considered blood a sacred sign of life.2 This teaching remains necessary for all time.
1 Gen 9:5-6.
2 Cf. Lev 17:14.