Related Rule
Israel
Practice Relating to Rule 137. Participation of Child Soldiers in Hostilities
In 2008, in its initial report to the Committee on the Rights of the Child under the 2000 Optional Protocol on the Involvement of Children in Armed Conflict, Israel stated:
[P]ersons aged 17–18, who volunteer for early military service, on their own initiative, pursuant to their written request, and according to the provisions declared by the State of Israel, are limited to military training until they attain 18 years, and do not take a direct part in hostilities. 
Israel, Initial report to the Committee on the Rights of the Child under the Optional Protocol on the Involvement of Children in Armed Conflict, 15 April 2009, UN Doc. CRC/C/OPAC/ISR/1, submitted 18 March 2008, § 7.
Israel further stated that “members of the Israel Defence Force … aged under 18, are not posted in combat duty and therefore do not take a direct part in hostilities”. 
Israel, Initial report to the Committee on the Rights of the Child under the Optional Protocol on the Involvement of Children in Armed Conflict, 15 April 2009, UN Doc. CRC/C/OPAC/ISR/1, submitted 18 March 2008, § 6.
Israel also stated:
There are no legal options to lower the recruitment age, in times of emergency and those who are not designated for service, but wish to do so, may assist in the performance of non-military activities that shall not constitute direct participation in hostilities. Therefore, any service volunteered for by persons under 18 will adhere to [the] objectives and spirit of the Optional Protocol, whilst still allowing these persons, to be actively engaged in civil aid of the State during a crisis. 
Israel, Initial report to the Committee on the Rights of the Child under the Optional Protocol to the Convention on the Rights of the Child on the Involvement of Children in Armed Conflict, 15 April 2009, UN Doc. CRC/C/OPAC/ISR/1, submitted 18 March 2008, § 27.