Blessed are the pure in heart, for they shall see God.
Matthew 5:8
If we are looking for that which is absolutely pure, we must look to God. Nothing in our natural state is pure. Even for the kindest, most sincere human beings, purity is something that eludes us. Purity can be defined as uncontaminated, perfect, flawless, and genuine. Again, these descriptions are reserved only for the things that pertain to God. Consider the following:
This is the message we have heard from Him and announce to you, that God is Light, and in Him there is no darkness at all.
1 John 1:5
Let no one say when he is tempted, “I am being tempted by God”; for God cannot be tempted by evil, and He Himself does not tempt anyone.
James 1:13
The law of the Lord is perfect, restoring the soul; the testimony of the Lord is sure, making wise the simple. The precepts of the Lord are right, rejoicing the heart; the commandment of the Lord is pure, enlightening the eyes.
Psalm 19:7-8
But the wisdom from above is first pure, then peaceable, gentle, reasonable, full of mercy and good fruits, unwavering, without hypocrisy.
James 3:17
God is Light and in Him there is no darkness at all. Although Light (Jesus) has come into the world, mankind loves darkness more than Light (John 3:19). This is why so many people reject Christ.
God cannot be tempted nor does He tempt anyone. When Jesus walked the earth, He was tempted by the devil. If He had succumbed to that temptation, He would have been blemished, stripped of His very purity and His becoming the spotless sacrifice for the sins of mankind would have been nullified. But He did overcome and because of His purity He is now the Savior of the world.
The Law of God is perfect and pure. The Law is not blemished but we are. That is why the Law is incapable of saving mankind. The problem is not with the Law merely our ability to keep it.
The wisdom of God is pure. Anytime we exercise spiritual discernment, we are operating in the wisdom and purity of God.
Pure religion is defined as that which takes care of others and guarding against being stained by the world (James 1:27). We are told to think on things that are pure (Philippians 4:8). David requested of God to create in Him a clean (pure) heart (Psalm 51:10).
So what do we do with all of this talk about purity? I believe that apart from Christ, we are incapable of purity. We must find our purity as a byproduct of knowing Jesus. Since all things pure are from God, purity can only flow from a life that is led by the Spirit of God.
My understanding is that there are people who check the whiteness of their teeth by holding up a tissue in order to make a comparison. We might think our teeth are white but after comparing them to a standard, we may change our mind. We should do the same with our lives. We might believe that we are doing good things and living a pretty upright life, but how do we look when we hold up our lives to the standard and perfection of God? Purity will come as we yield our lives to the only One who can claim absolute purity.
All the ways of a man are clean (pure) in his own sight, but the Lord weighs the motives.
Proverbs 16:2
How can a young man keep his way pure? By keeping it according to Your word.
Psalm 119:9