My words [shall be of] the uprightness of my
heart
Not that the uprightness of his heart, or his own personal
integrity, should be the subject of his discourse; but what he
should say would be in or out of the uprightness of his heart,
with all sincerity and faithfulness; what would be the real
sentiments of his mind, and not proceed from a double or
insincere heart:
and my lips shall utter knowledge clearly;
what knowledge he had of God, and of the perfections of his
nature, and of his works in nature and grace, and of his dealings
in a providential way with the sons of men; and what knowledge he
had of Christ, his person, office, and grace somewhat of which
speaks in this chapter; and such sort of knowledge is to be
uttered, to be published, and made known to the good of others;
and not to be concealed, and hid, or held, as in a prison, in
unrighteousness; and to be uttered clearly, plainly, and
distinctly, in words intelligible, and easy to be understood; and
not in ambiguous terms, or in words of a double meaning; or which
are abstruse and intricate, and serve rather to make the
mysteries of Providence and grace more dark and obscure than to
explain them; integrity of heart, and perspicuity of language,
serve much to recommend a speaker, and both are expressed in this
verse.