For the phrases “For though your people Israel were like the sand of the sea, only a remnant of them will return. Destruction is decreed, overflowing with righteousness. For the Lord God of hosts will make a full end, as decreed, in all the earth,” see Romans 9:27 and Romans 9:28.

Note that this quote in the New Testament is not taken from the Hebrew Bible but from the Greek Septuagint (LXX) which translates into English as “And if the people of Israel become like the sand of the sea, the remnant will be saved, for he is completing and cutting short a reckoning with righteousness, because God will perform a shortened reckoning in the whole world.'” (Translation by NETS — for the Greek version see the title’s tooltip)