Not sure if it's been mentioned, but Michael Brown, himself, admits multiple times in that first episode that the Roman Catholic Church changed the Sabbath day to Sunday; and also admits that he doesn't think that was right. This fact is well known to those who have researched this topic in depth and the Catholic Church itself has publicly admitted it.
Furthermore, the answer he is demanding is locked into a box, if you will, that only allows for specific wording in just such a way that the proof he is challenging someone to produce (a specific verse from the NT that states that God commanded the Gentiles to observe the 7th Day Sabbath) does not exist. He knows it does not exist and that is why he issued the challenge on 'his' show.
Despite his efforts to thwart his listeners' ability to prove the actual point of contention (that the Saturday Sabbath 'should' still be observed by modern Christians), there were callers who proved that point very succinctly who he either cut off, spoke over, went to commercial or otherwise silenced.
At 37:00 the caller pointed out Acts 13:42-44, one of the best indicators in scripture that the Saturday Sabbath 'was' observed by the Apostle Paul and Gentiles 'after' the crucifixion. As soon as the caller made that statement, Michael Brown ridiculed him and dismissed his argument as nonsense and ended his call, effectively attacking the caller and not the caller's argument. Textbook example of someone desperately redirecting the audience's attention away from the point made and attempting to garner their support in the implication that the caller's statement was ridiculous. Michael also followed immediately with a statement claiming that Christians gathered for worship on Sunday all the way back to the early church which is completely unscriptural and only true 'after' the 3rd century when it was made law by the Roman Emperor Constantine. There is absolutely no verse in the Bible about Sunday worship. Not one.
The point the caller was making was Acts 13:42-44 where Paul was leaving the synagogue, after preaching on the Saturday Sabbath, and was begged by the 'Gentiles' to preach to them the next Sabbath. If 'any' of the Apostles or 'anyone' significant had been observing a Sunday Sabbath or a day of worship of any kind on Sunday, Paul would've simply told them to come back the very next day to hear him preach again. That is 'not' what happened. And the Bible makes very clear that "almost the whole city came together to hear the Word of God" on the following Sabbath.
This 'IS' a New Testament example.
This is Paul, widely referred to as the Apostle to the 'Gentiles', preaching on the Saturday Sabbath 'AFTER' the crucifixion of Christ.
*For all those interested, there are countless verses in scripture that prove the Saturday Sabbath. Here are just a few:
(Gen. 2:1-3) God blessed the 'Seventh Day', mentioned 'Three Times' in the first three verses of the Bible.
(Ezek. 20:12) God gave us the Sabbath as a sign 'Forever' (For all eternity) between us and Him.
(Isa. 66:23) All believers will be keeping the Sabbath for eternity in Heaven.
(Num. 23:20) God's blessings cannot be reversed.
(1 Chron. 17:27) What the Lord blesses shall be blessed forever.
(Exod. 20:8-11) God's command.
(Matt. 28:1) The only mention in Matthew of the first day of the week, in 70 A.D. about 40 years after the time of Christ, totally silent about Sunday worship.
(Mark 16:2,9,14) Only mention of first day of week in Mark, 60 A.D., nothing about Sunday worship.
(Luke 24:1) Only mention of first day of week in Luke, 80-90 A.D., nothing about Sunday worship.
(Luke 4:16) Jesus' regular custom was to stand and read scripture in the synagogue on the Saturday Sabbath.
(Matt. 24:15-22) Jesus makes clear that He expects His disciples to still be observing the Saturday Sabbath 40 years after His death and resurrection. (Note: This was 'not' spoken only to the Jews as can be seen in 24:3. Jesus is speaking to His disciples 'privately.')
(Luke 23:56) Jesus' disciples honored the Saturday Sabbath instead of finishing tending to His crucified body.
(Rev.1:10) John on the island of Patmos, 95 A.D., refers to 'The Lord's Day.' (Saturday Sabbath)
(Isa. 58:13) God, through Isaiah, calls the Sabbath "My Holy Day" thus proving through scripture that John was referring to the Saturday Sabbath in Rev. 1:10.
(Mark 2:27) The Sabbath was made for 'man,' not just for the 'Jews.'
(Matt. 12:8) Jesus is the Lord of the Seventh Day, Saturday Sabbath. (No man has the authority to ever change that.)
(Heb. 13:8) Jesus is the same yesterday, today and 'FOREVER.'
(Mal. 3:6) I am the Lord, I change not.
(Matt. 5:18) Jesus says 'none' of the Law shall pass away until Heaven & Earth are completely gone.
(Acts 18:4) Paul preached in the Corinth synagogue every Saturday Sabbath for 18 months. (New Testament, after Jesus' death and resurrection.)
*Interesting facts about the Sabbath:
-There are many languages that still use a word for Saturday that means 'Sabbath.'
-There are exactly 59 mentions of the Sabbath, by name, in the New Testament. (*Referring to Saturday.)
-Paul preached a total of 79 Sabbaths in Corinth to the Corinthians. (Paul's time as an Apostle was after the crucifixion of Jesus. *Very significant.*)
-The book of Acts, alone, records 84 separate Sabbaths that Paul & others attended as the newly formed Christian Church.
-Not once in the New Testament did the Apostles gather in worship on Sunday for the declared purpose of honoring the resurrection.
-Not once in the Gospels, nor the NT as a whole, did Jesus even mention the first day of the week, nor did He declare it the new day of rest to replace the Saturday Sabbath.
-The Sabbath is the 'only' day ever to be blessed by God. (And as such can never be changed by anyone ever created by Him after. What God blesses can never be undone.)
-God gave the Seventh Day Sabbath to Adam & Eve, 2500 years before Moses ever gave it to the 'Jews' among the 10 Commandments.