'Do You Not Know' in the Bible

Do you not know that when you continually offer yourselves to someone to do his will, you are the slaves of the one whom you obey, either [slaves] of sin, which leads to death, or of obedience, which leads to righteousness (right standing with God)?

Or do you not know, brothers and sisters (for I am speaking to those who know the Law), that the Law has jurisdiction [to rule] over a person as long as he lives?

God has not rejected His [chosen] people whom He foreknew. Or do you not know what the Scripture says of Elijah, how he pleads with God against Israel?