Afterwards mantras had been employed much more to protect the spiritual life of the chanter, and sections on mantras started to be included in some Mahayana sutras like the White Lotus Sutra, as well as the Lankavatara Sutra. The scope of security also modified During this time. From the Sutra https://bookmarkworm.com/story18803404/an-unbiased-view-of-upay