“Honestly” in the phrase of “honestly casting away the expedient” stated in the sūtra means that when a beginner practices the Lotus Sūtra, the beginner should be devoted to practicing solely the Lotus Sūtra, casting away all the other sūtras mentioned before; such is a really honest practicer. If, on the contrary, a beginner practices the various sūtras and the Lotus Sūtra simultaneously, just like highly trained bodhisattvas, this person would surely be regarded as a dishonest practicer. As the proverbs say: “A sage never served two rulers;” and “A virtuous wife does not remarry;” they describe the honest practicer.

Shimoyama Goshōsoku, The Shimoyama Letter, Writings of Nichiren Shōnin, Volume 5, Page 69