The duck idiom says “if you look like a duck, swim like a duck, quack like a duck, you must be a duck.” According to abductive reasoning this may or may not be true but it does reflect how we might be seen in the world. We have melded into the fabric of society and no one knows we are not a duck but a believer in Christ. Therefore, Paul reminded his readers to not be conformed or molded into the world’s system just like the frog scenario. We are put into the pot and the enemy heats up the water but we are unaware that we are being cooked!
Also, just as a salmon swims against the flow of the river to achieve its place to spawn so we must swim against the false current of the world’s philosophy. The salmon faces many trials to arrive so too we will trials and enemies. Therefore we must be saturated with the Word so that we can discern truth from error. [Heb 5:14] We have this promise: He who hath begun a good work in you will complete it at the day of Christ but until then we are moment by moment being filled with the Holy Spirit. It is His work that is being accomplished as we surrender and become a living sacrifice. It is all His power and all because we are a new creation in Christ. He enables us to “behold the glory of the Lord.” (2Cor 3:18] This is how the mind is renewed — by steadfastly gazing at the glories of Christ for what they really are.
How does the world see us; ducks, frogs, salmon or a transformed believer in Christ?