梵網經菩薩戒本疏 6.103

6.103

初、制意者，大願熏修令萬行增長，不立弘誓行起無由，故須制也。《華嚴》云：不發大願為魔業。

First, regarding the purpose of the prohibition: great vows perfume and cultivate so as to make the myriad practices grow; if vast vows are not established, practice has no way to arise; hence it had to be prescribed. The Avataṃsaka Sūtra states: 'Not making great vows is the work of Māra.'