Teaching on the Trinity can be challenging, not because it’s not biblical–but rather because it is supra-rational. Yet the Scriptures do indeed reveal the one true God as Triune.
Charles Heinze’s brief but excellent book, Trinity and Triunity, has two excellent analogies that illustrate the concept of the Trinity. See http://www.angelfire.com/va/sovereigngrace/trinityandtriunity1.html
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The Virgin Birth by Robert Gromacki