pron. An emphasized form of the personal pronoun of the second person; -- used as a subject commonly with thou; as, thou thyself shalt go; that is, thou shalt go, and no other. It is sometimes used, especially in the predicate, without thou, and in the nominative as well as in the objective case. [ 1913 Webster ]

Thyself shalt see the act. Shak. [ 1913 Webster ]

Ere I do thee, thou to thyself wast cruel. Milton. [ 1913 Webster ]