“God created man out of the dust of the earth, and made and formed him after His own image and likeness, good, righteous, and holy, capable in all things to will agreeably to the will of God” (BC, article 14). This means that the first human beings, Adam and Eve, did not evolve from an animal ancestry (or any kind of subhuman species); and all other men and women are descendants of Adam and Eve.
God entered into a covenant with Adam and in him all his posterity, promising life for obedience and death for disobedience (Genesis 2:16-17). But man “willfully subjected himself to sin and consequently to death and the curse, giving ear to the words of the devil.” For he transgressed the covenant; “and by sin separated himself from God, who was his true life; having corrupted his whole nature; whereby he made himself liable to physical and spiritual death [Romans 5:12; Ephesians 2:1]” (BC, article 14). This corruption of the whole nature [original sin] is a hereditary disease which extends to all mankind. We are all conceived and born in sin [Psalm 51:5]. Thus, man’s will is no longer free to obey God’s will, but man is now “a slave of sin [Romans 3:22], and can receive nothing, unless it has been given to him from heaven (John 3:28). For who may presume to boast that he of himself can do any good, since Christ says: No one can come to Me, unless the Father who sent Me draws him (John 6:44)?” (BC, article 14).