The *Catechism of the Catholic Church * states:
1867: The catechetical tradition also recalls that there are “sins that cry to heaven”: the blood of Abel,139 the sin of the Sodomites,140 the cry of the people oppressed in Egypt,141 the cry of the foreigner, the widow, and the orphan,142 injustice to the wage earner.143
139 Cf. Gen 4:10.
140 Cf. Gen 18:20; 19:13.
141 Cf. Ex 3:7-10.
142 Cf. Ex 20:20-22.
143 Cf. Deut 24:14-15; Jas 5:4.
2268: The fifth commandment forbids direct and intentional killing as gravely sinful. The murderer and those who cooperate voluntarily in murder commit a sin that cries out to heaven for vengeance.69 Infanticide,70 fratricide, parricide, and the murder of a spouse are especially grave crimes by reason of the natural bonds which they break. Concern for eugenics or public health cannot justify any murder, even if commanded by public authority.
69 Cf. Gen 4:10.
70 Cf. GS 51 § 3.
