Unfortunately, the unibeliever already knows this. On other threads he has posted the CCC excerpt that says essentially what you said to him. That just is not good enough for him here. He wants to see "veneration of images" spelled out word for word in scripture.
Of course it is not spelled out word for word in scripture, any more than "Trinity," as we understand it today, is spelled out LITERALLY in scripture.
He does not realize that his manner of debating veneration is the same as the JW's manner of debating "Trinity."
If he were consistent in his scriptural demands, he would be a JW, denying the reality of the Trinity as Christians understand it today. But he does not let logical inconsistency cloud his anti-Catholic bigotry.
I know. I'm not really talking to him or the others whose cults are founded on an anti-theology of rebellion, rather than on faith, but to those who are already open to the truth. They're not as noisy, but they're out there, and they read what we write.
There is not the slightest hint to support you but plenty of condemnation of idolatry.
Of course it is not spelled out word for word in scripture, any more than "Trinity," as we understand it today, is spelled out LITERALLY in scripture.
I JOHN 5:6 ¶ This is he that came by water and blood, [even] Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth.
I JOHN 5:7 For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one.
I JOHN 5:8 And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one.
I JOHN 5:9 If we receive the witness of men, the witness of God is greater: for this is the witness of God which he hath testified of his Son.