“that their hearts may be encouraged, being knit together in love, and attaining to all riches of the full assurance of understanding, to the knowledge of the mystery of God, both of the Father and of Christ”
The third line of defense for the Christian is his certainty of truth.
“and attaining to all riches of the full assurance of understanding”
If a man does not possess certainty of truth, then an error will eventuate. If what we hold today is gone tomorrow, we enter into dubiety and fluctuation where truth can never be fixed. Tolerance of every wind of doctrine becomes the only central norm for determining reality. If new ideas chase away convictions, spiritual instability will result. If what we hold today is gone tomorrow, truth cannot be eternal or absolute. What does that say about an eternal, absolute God? The mind becomes susceptible to constant question and influence without a revelation of God in Scripture.
Fixed knowledge of truth fortifies the mind against false teachers. It is less likely to become seduced by insinuations that contain some truth and some error. The mind most susceptible to seduction is the mind that possesses an incomplete, one-sided view of the issue. It is unable to reconcile conflicting challenges to its bias. That person is much more liable to become seduced because he is constantly off balance. He is perpetually disturbed and perplexed by conflicting ideas that were insufficiently formed in the first place.
A person traveling in unfamiliar territory is much more vulnerable to becoming lost. He may begin to doubt his direction. He becomes more prepared to listen to other suggestions, no matter how capable they may be. No wonder “full assurance” is described here as “riches!”
The combination of great knowledge and strong faith makes a rich spirit. The word “riches” is the word from which we get the word thesaurus. We live in a day of tolerance and vacillation. We are so pliable that we view someone who holds convictions as abnormal.
The word “understanding” means acuteness of comprehension or penetrating intelligence before decision and action. This is reflective and productive thought. “Understanding” is the basis for recovering from instability.
Confidence comes from an acute comprehension of the divine truth of God.
If a believer understands the underlying principles of the Word, he or she can apply truth to their situation. If not, they wobble throughout their Christian life. Truth stabilizes the Christian life. If we live by our emotional bootstraps, we will become vulnerable to every wind of doctrine that comes down the pike. If we live by truth, we will recover from instability. We hold a frame of reference whereby we can categorize any challenge to truth and measure it against the Word of God. Having done that, we can correctly assess the proper practical course of action.