A little study to help determine how we should take care in declaring, "clearly this is true." 
I found it interesting, having spent a little time studying philosophy, looking at what the Bible says is "certain." A lot of philosophy consists of trying to figure out what we can be certain of. Philosophy considers important things like sensory experience, or things in the world relative to our sensory organs, along with our subjective experience.
I found the following passage interesting, in this regard, because it talks about things man kind can universally find certain, even though there remain unbelievers. Strikingly, Paul finds no contradiction in a certainty in "seeing" the *invisible God!* In other words, subjective experience is virtually as certain as what our senses perceive!...
Rom 1.20 For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen/non-turbid [kathoratai], being understood from what has been made, so that people are without excuse.
So we can "clearly see" what is invisible about God! We should not be afraid to declare things of faith even though they are unseen.
We see this clarity also in the river of the water of life in the New Jerusalem...
Rev 22.1 Then the angel showed me the (pure/non-turbid) [katharos] river of the water of life, as clear/splendid (lampron) as crystal, flowing from the throne of God and of the Lamb.
The following passages indicate things are made clear as a logical deduction based on appearances (deelos). We should not be afraid of making *logical deductions.*
1 Cor 15.27 For he “has put everything under his feet.” Now when it says that “everything” has been put under him, it is clear (manifestly evident) [deelos] that this does not include God himself, who put everything under Christ.
Gal 3.11 Clearly (logically) [deelos] no one who relies on the law is justified before God, because “the righteous will live by faith.”
2 Tim 3.9 But they will not get very far because, as in the case of those men, their folly will be clear (apparent) [ekdeelos] to everyone.
Heb 7.14 For it is clear (obvious) [prodeelon] that our Lord descended from Judah, and in regard to that tribe Moses said nothing about priests.
Heb 7.15 And what we have said is even more clear (apparent) [katadeelon] if another priest like Melchizedek appears.
2 Pet 1.14 because I know that I will soon put it aside, as our Lord Jesus Christ has made clear (made apparent) [edeelosen] to me.
The following passages indicate that things are clear as a demonstrative manifestation. We should try to make something obviously true, as well as logical.
2 Cor 11.6 I may indeed be untrained as a speaker, but I do have knowledge. We have made this perfectly clear (manifestly evident) [phanero] to you in every way.
Col 4.4 Pray that I may proclaim it clearly (self-evidently manifest) [phanero], as I should.
Phil 1.13 As a result, it has become clear (self-evidently manifest) [phaneros] throughout the whole palace guard and to everyone else that I am in chains for Christ.
Another form of making clear is something previously documented. We should be ready to back things up with Scriptures.
Gal 3.1 You foolish Galatians! Who has bewitched you? Before your very eyes Jesus Christ was clearly portrayed (previously documented) [proegraphe] as crucified.
Another form of making clear is something revealed. We should recognize that clarity requires divine revelation.
Phil 3.15 All of us, then, who are mature should take such a view of things. And if on some point you think differently, that too God will make clear (reveal) [apokalupsei] to you.
Another form of making clear is verbally asserting or declaring. We should recognize that words can have power to make clear.
1 Tim 4.1 The Spirit clearly says (in words) [retos] that in later times some will abandon the faith and follow deceiving spirits and things taught by demons.
Another form of making clear is explaining or interpreting. Making clear can be a studied exercise.
Heb 5.11 We have much to say about this, but it is hard to make it clear (difficult to explain or interpret) [dysermeneutos} to you because you no longer try to understand.
Another form of making clear is to point out or visually show. Visuals are important to prove some things.
Heb 6.17 Because God wanted to make the unchanging nature of his purpose very clear (visually show/physically prove) [epideixai] to the heirs of what was promised, he confirmed it with an oath.
Another form of making clear is via the symbolic use of a sea of glass with crystal transparency, as well as to the New Jerusalem, with a splendid/non-turbid river. The Bible uses symbols to show the importance of purity in clarifying things.
Rev 4.6 Also in front of the throne there was what looked like a sea of glass, clear as crystal [krystalio]. In the center, around the throne, were four living creatures, and they were covered with eyes, in front and in back.
Rev 21.11 It shone with the glory of God, and its brilliance was like that of a very precious jewel, like a jasper, clear as crystal [krystallizonti].
Here, the crystal is connected to its splendid clarity.
Rev 22.1 Then the angel showed me the (pure/non-turbid) [katharos] river of the water of life, as clear/splendid (lampron) as crystal, flowing from the throne of God and of the Lamb.
If this helps nobody else, it helped me! I'm not well-acquainted with Greek, but even the novice can make certain deductions from the manifold internet resources!
I found it interesting, having spent a little time studying philosophy, looking at what the Bible says is "certain." A lot of philosophy consists of trying to figure out what we can be certain of. Philosophy considers important things like sensory experience, or things in the world relative to our sensory organs, along with our subjective experience.
I found the following passage interesting, in this regard, because it talks about things man kind can universally find certain, even though there remain unbelievers. Strikingly, Paul finds no contradiction in a certainty in "seeing" the *invisible God!* In other words, subjective experience is virtually as certain as what our senses perceive!...
Rom 1.20 For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen/non-turbid [kathoratai], being understood from what has been made, so that people are without excuse.
So we can "clearly see" what is invisible about God!
We should not be afraid to declare things of faith even though they are unseen. We see this clarity also in the river of the water of life in the New Jerusalem...
Rev 22.1 Then the angel showed me the (pure/non-turbid) [katharos] river of the water of life, as clear/splendid (lampron) as crystal, flowing from the throne of God and of the Lamb.
The following passages indicate things are made clear as a logical deduction based on appearances (deelos). We should not be afraid of making *logical deductions.*
1 Cor 15.27 For he “has put everything under his feet.” Now when it says that “everything” has been put under him, it is clear (manifestly evident) [deelos] that this does not include God himself, who put everything under Christ.
Gal 3.11 Clearly (logically) [deelos] no one who relies on the law is justified before God, because “the righteous will live by faith.”
2 Tim 3.9 But they will not get very far because, as in the case of those men, their folly will be clear (apparent) [ekdeelos] to everyone.
Heb 7.14 For it is clear (obvious) [prodeelon] that our Lord descended from Judah, and in regard to that tribe Moses said nothing about priests.
Heb 7.15 And what we have said is even more clear (apparent) [katadeelon] if another priest like Melchizedek appears.
2 Pet 1.14 because I know that I will soon put it aside, as our Lord Jesus Christ has made clear (made apparent) [edeelosen] to me.
The following passages indicate that things are clear as a demonstrative manifestation. We should try to make something obviously true, as well as logical.
2 Cor 11.6 I may indeed be untrained as a speaker, but I do have knowledge. We have made this perfectly clear (manifestly evident) [phanero] to you in every way.
Col 4.4 Pray that I may proclaim it clearly (self-evidently manifest) [phanero], as I should.
Phil 1.13 As a result, it has become clear (self-evidently manifest) [phaneros] throughout the whole palace guard and to everyone else that I am in chains for Christ.
Another form of making clear is something previously documented. We should be ready to back things up with Scriptures.
Gal 3.1 You foolish Galatians! Who has bewitched you? Before your very eyes Jesus Christ was clearly portrayed (previously documented) [proegraphe] as crucified.
Another form of making clear is something revealed. We should recognize that clarity requires divine revelation.
Phil 3.15 All of us, then, who are mature should take such a view of things. And if on some point you think differently, that too God will make clear (reveal) [apokalupsei] to you.
Another form of making clear is verbally asserting or declaring. We should recognize that words can have power to make clear.
1 Tim 4.1 The Spirit clearly says (in words) [retos] that in later times some will abandon the faith and follow deceiving spirits and things taught by demons.
Another form of making clear is explaining or interpreting. Making clear can be a studied exercise.
Heb 5.11 We have much to say about this, but it is hard to make it clear (difficult to explain or interpret) [dysermeneutos} to you because you no longer try to understand.
Another form of making clear is to point out or visually show. Visuals are important to prove some things.
Heb 6.17 Because God wanted to make the unchanging nature of his purpose very clear (visually show/physically prove) [epideixai] to the heirs of what was promised, he confirmed it with an oath.
Another form of making clear is via the symbolic use of a sea of glass with crystal transparency, as well as to the New Jerusalem, with a splendid/non-turbid river. The Bible uses symbols to show the importance of purity in clarifying things.
Rev 4.6 Also in front of the throne there was what looked like a sea of glass, clear as crystal [krystalio]. In the center, around the throne, were four living creatures, and they were covered with eyes, in front and in back.
Rev 21.11 It shone with the glory of God, and its brilliance was like that of a very precious jewel, like a jasper, clear as crystal [krystallizonti].
Here, the crystal is connected to its splendid clarity.
Rev 22.1 Then the angel showed me the (pure/non-turbid) [katharos] river of the water of life, as clear/splendid (lampron) as crystal, flowing from the throne of God and of the Lamb.
If this helps nobody else, it helped me!
I'm not well-acquainted with Greek, but even the novice can make certain deductions from the manifold internet resources!
