大毘盧遮那成佛經疏 9.79

9.79

右句義中，摩訶阿摩訶是大無大義，怛他蘗多爾訶嚩是如來舌義，此舌廣長之相遍覆一切佛剎，故名為大。此大更無過上故、無可待對故、大相亦不可得故，名為無大。次云薩底也（二合）是諦，達摩是法，鉢囉𫪭瑟恥多是成就，譯云成就實諦法也。如來無量劫來常修真實諦語故，得此平等語輪。成就實諦之法，所發誠言必定無異，故以最後多字為真言體。明如來所有語言，常如實相無誑無異也。阿闍梨以此加持身故，轉說法教皆如金剛，乃至能以一音遍諸佛剎。凡此諸真言等，皆當以字門廣釋之。

In the meaning of the phrases above: mahā-amahā means great and non-great; tathāgata-jihva means the Tathāgata's tongue. The broad and long mark of this tongue covers all buddha-lands, so it is called 'great.' Because there is nothing superior to this greatness, nothing to compare it against, and the mark of greatness itself is ungraspable, it is called 'non-great.' Next, satya means truth; dharma means Dharma; pratiṣṭhita means established, translated as 'established in the true and real Dharma.' Because the Tathāgata has constantly cultivated true and real speech for immeasurable kalpas, he attains this wheel of equal speech. Established in the true and real Dharma, the sincere words he utters are definitively without variation; therefore, the final syllable ta is taken as the essence of the mantra. It explains that all words of the Tathāgata are constantly in accord with dharmatā, without deception and without variation. Because the ācārya empowers his body with this, all the teachings of the Dharma he expounds are like vajra, even able to pervade all buddha-lands with a single sound. In general, all these mantras should be broadly explained by means of the syllable gateways.