'Thing' in the Bible

I am convinced and confident of this very thing, that He who has begun a good work in you will [continue to] perfect and complete it until the day of Christ Jesus [the time of His return].

who, although He existed in the form and unchanging essence of God [as One with Him, possessing the fullness of all the divine attributes—the entire nature of deity], did not regard equality with God a thing to be grasped or asserted [as if He did not already possess it, or was afraid of losing it];

Brothers and sisters, I do not consider that I have made it my own yet; but one thing I do: forgetting what lies behind and reaching forward to what lies ahead,