After his release, in 1995 Jabari began to act as a commander in the military wing of the Hamas. In addition, he dealt with the movement's charitable organizations and was responsible for coordinating between the collection of money and military activities. In the middle of the 1990s, Jabari was directly involved in planning suicide bombings against Israeli citizens. Then, due to his involvement with these military activities in the Gaza Strip, Jabari was arrested by the Preventive Security Force of the Palestinian Authority in October 1998 for his alleged role in the Kfar Darom bus attack. He was released in late 1999. After his release he became an assistant of Salah Shehadeh and Mohamed Aldahef, the commanders of the military wing, in charge with improvement of military actions. Thus, he was part of Hamas's high-ranking military leadership during the first intifada and of the first Intifada cell.