In discussing the use of covenants in the ancient Near East, Harless points out that a covenant is “a solemn unilateral obligation made binding by an oath” (p. 12). Of the three kinds of covenants, the parity and suzerainty covenants are conditional and the grant covenant is unconditional.
The Edenic, Adamic, and Mosaic covenants are suzerainty covenants (conditional), and the Noahic, Abrahamic, Land, Davidic, and New covenants are grant covenants (unconditional).
In his thorough discussion of each of these eight biblical covenants Harless discusses the type of covenant, the covenant’s beneficiaries, the stipulations, when and how the covenant was established, and its duration.
Then he discusses the duration, characteristics, and stipulations of the seven biblical dispensations, and also the covenants that were or are in force during those dispensations.
A helpful chart on page 79—one of many charts in the book—depicts which covenants extend through the duration of which dispensations. For example the Adamic Covenant extends through all the dispensations except the dispensation of innocence, the Noahic Covenant extends through five dispensations (all except the first two, innocence and conscience), and the Abrahamic Covenant extends through the four dispensations of promise, law, grace, and kingdom. The New Covenant was established by the death of Christ, with Israel as the future beneficiaries in the millennium and with the church now enjoying the spiritual blessings of that covenant.
Harless states the relationship between the biblical covenants and the dispensations in this way: “A dispensation is an administration of all of the covenantal stipulations in force at the time” (p. 58, italics his).
As many dispensationalists have pointed out, the promises in the Land and Davidic covenants are unconditional, but the enjoyment of those promises is conditioned on obedience (pp. 137, 153).
Harless notes that covenant theologians teach three covenants, no one of which is specified in the Scriptures: the covenant of redemption, the covenant of works, and the covenant of grace. Thus they say relatively little about the eight biblical covenants, and of course they deny the existence of the biblical dispensations. Dispensationalists, on the other hand, he says, have not adequately discussed the relationship between the biblical covenants and the dispensations. His thoroughly biblical discussion is a strong defense and clarification of certain aspects of dispensationalism.