Arop was 4 of 7 from the field, and Gant was 4 of 8 for the Sycamores (10-5, 3-1 Missouri Valley).
The Sycamores led 28-25 at halftime and never trailed in the second half.
Indiana Sate shot 50 percent from the field for the game. Bradley shot 31.8 percent. Bradley had only one field goal in the final 8:25.
Walt Lemon Jr. led Bradley (Bradley 10-6, 2-2) with 15 points, with 10 coming in the first half. Jake Eastman had eight rebounds.
Dyricus Simms-Edwards scored nine points, joining Bradley's 1,000-Point Club.
The win gives Indiana State a 3-1 start to MVC play, its best since the 2007-08 season when it also started 3-1.