維摩經略疏垂裕記 7.179

7.179

二、一往橫明，二：初、懸示分科。「以橫望竪」者，圓心之橫，收別之竪。以阿字門具諸地故，故成高廣。

Second, tentatively clarifying horizontally, which has two [parts]: first, prefatory indication and dividing into sections. Regarding "viewing the vertical from the horizontal": the horizontal of the perfect mind includes the vertical of the separate [teaching]. Because the syllable 'A' gate contains all stages, it therefore becomes lofty and broad.