Being - Vine's Expository Dictionary of New Testament Words
Being
* When not part of another verb (usually the participle), or part of a phrase, this word translates one of the following:(a) the present participle of eimi, to be," the verb of ordinary existence;
(b) the participle of ginomai, "to become," signifying origin or result;
(c) the present participle of huparcho, "to exist," which always involves a preexistent state, prior to the fact referred to, and a continuance of the state after the fact. Thus in Philippians 2:6, the phrase "who being (huparchon) in the form of God," implies His preexistent Deity, previous to His birth, and His continued Deity afterwards.
In Acts 17:28 the phrase "we have our being" represents the present tense of the verb to be, "we are."