God is in and through everything, and elects those persons to the life and tasks, including covenants and dispensations, that God needs fulfilled in order to accomplish His divine purpose(s).
Really like this, have felt this way for a number of years. Would love to hear more on it
The basic concept is rather simple, but not simplistic. God has acted in history through individuals that He has selected, made covenants with those people, there have been eras, revelation and progressive revelation, prophets who foretold and forth-told God's word and future events, and then came Messiah -- Jesus Christ -- the fulfillment of that history and promise.
Just to make sure we're on the same page we're talking about two different types of theology here. Systematic theology deals with things like God, Trinity, Revelation, Creation, Divine providence, Christology, Soteriology, Ecclesiology, Eschatology, Israelology, Bibliology, Hermeneutics, Sacrament, Pneumatology, Christian life, Heaven, etc. It then attempts to wrestle from the text of Scripture the verses and principles that build these doctrines. This is the primary thing that we argue about on this board ad nausem. Biblical theology, on the other hand, is an attempt to build a theology based on the passages of Scripture, discovering the "center" or major points that drives the theology, with the result not a better understanding of various points of doctrine, but understanding God and God's purpose(s).
The difficulty in a biblical theology is in finding that "center." That one descriptor that holds together all the major themes of the Bible from start to finish. Dispensational theology attempts to do so by creating a framework based on historical "dispensations" or eras, where God seemed to be doing this or that, then building a case for future events based on that framework. Covenantal theology does likewise, but focuses on the covenants of God as the defining moments, but it misses the boat right out of gate because it starts with two covenants that are not covenants in any meaningful or biblical way -- the covenant of works (Adam, pre-fall) and the covenant of grace (the rest of the history of the world), as it then adds in specific biblical covenants under the main heading, covenant of grace.
Neither is correct, and both are mere frameworks applied over Scripture to try to make sense of the overall picture. Theologians have noticed this for ages, but no one has really put forward a usable picture, until now, it seems.
There as been a lot of debate about the true "center" of Scripture -- dispensation, covenant, the line of Christ, etc., but election seems to be the one thing that covers all the bases, for it handles every action of God, whether dispensation, era, person, action, etc. As God elects, things happen and history presses forward.
Of note, this is not a purely Calvinistic doctrine, though many Calvinists would gravitate in this direction, as most have rejected both dispensational and covenantal theologies for the reasons above (plus others I've not mentioned). The mere use of the word "election" does not make this a Calvinist doctrine. Election is a biblical word that all of us have to deal with somehow.