Why does the Bible refer to the Spirit as "itself" rather than "himself"?

Why do the Scriptures refer to the Spirit of God as "itself" occasionally?

The Spirit is twice referred to as "itself" in Romans 8:16 and 26. Greek students tell us that the pronoun in the original is neuter in strict grammatical agreement with the word "Pneuma" (Spirit), a neuter word. Since the Spirit is a person in the Godhead, other translations read, "Himself."

Our Lord Jesus used the masculine pronoun "He" with the neuter "Spirit" in John 14:16, 17; John 15:26; John 16:7,8,13. Using this "phenomenon of grammar," as another has called this exceptional use of the masculine pronoun, He shows that the Spirit is a person.

W. Gustafson