梵網經菩薩戒本疏 6.61

6.61

五、闕緣者，隨闕一緣皆重方便，亦本末二方便罪也。並準思可見。

Fifth, lacking conditions: Whenever any one condition is lacking, it is a grave preparatory offense, which is also the two preparatory offenses of root and branch. Both can be understood by contemplating in accordance with this.