Unlike some countries that may not pay much attention to the issue of the EFL teacher being certified/uncertified, Israel is rather strict about the qualifications of the teachers.
It may be helpful to take the course and get certified in TEFL in your home country. Although it is not obligatory in Israel, it will be quite an advantage when searching for a job.
A standard requirement is to have a four-year university or college degree in any discipline, which may not necessarily be connected with English language/literature, linguistics or teaching. People without college graduation should consider working in other countries.
Becoming a certified teacher in Israel is another privilege, which may be a key motive force in getting a job place. The most reputable English-teaching center is the TESOL (Teachers of English to Speakers of Other Languages) organization in Tel Aviv. It offers 4-week courses, which teach the basic skills for effective communication and teaching in ESL classrooms.
Of course, you may try finding a job without a proper certification, but hat may tack much time, effort and don’t bring satisfying result (the salary may be lower than the average for the EFL teachers, or conditions of work may be unsatisfying). On the contrary, getting a certification will surely result in the quick and perspective job offer, and you will be able enjoy all the privileges the educational institutions propose to the EFL teachers.