Their, Theirs - Vine's Expository Dictionary of New Testament Words
Their, Theirs
* Note: These pronouns are the rendering of(1) auton, the genitive plur. of autos, he," e.g., Matthew 2:12;
(2) heauton, "of themselves," the genitive plur. of heautou, "of himself," e.g., Matthew 8:22; Romans 16:4, Romans 16:18, "their own;" or the accusative plur. heautous, e.g., 2 Corinthians 8:5, "their own selves" (for John 20:10, See HOME, A, No. 3);
(3) idious, the accusative plur. of idios, "one's own," e.g., 1 Corinthians 14:35, "their own;"
(4) touton, lit., "of these," the gen. plur. of houtos, "this," Romans 11:30, "their (disobedience);"
(5) ekeinon, the gen. plur. of ekeinos, "that one" (emphatic), e.g., 2 Corinthians 8:14 (twice), "their," lit., "of those;" 2 Timothy 3:9, "theirs."