Pastor James McConnell, 78, has been on trial following a sermon in which he branded Islam "heathen", "satanic" and a "doctrine spawned in hell".
District Judge Liam McNally told Belfast Magistrates' Court: "We have come to the end of an interesting three days.
"Obviously I am going to reserve my judgment. I want to consider all the points raised in submissions."
The pensioner is being prosecuted under the 2003 Communications Act and faces two charges - improper use of a public electronic communications network and causing a grossly offensive message to be sent by means of a public electronic communications network.
Both relate to comments made from the pulpit of his Whitewell Metropolitan Tabernacle on May 18 2014.
Mr McConnell denies the charges.
The judge said he was "anxious" to deliver a verdict early in the new year and set a deadline of January 5.
Addressing the courtroom which was filled to capacity with born again Christian supporters, Judge McNally said: "I want to wish you all a happy and holy Christmas."
In his closing submissions, prosecutor David Russell QC said it was a "straightforward" case.
The pastor was "not on trial for his beliefs" but for what he said and using words which were allegedly "grossly offensive", the court heard.
Mr Russell said: "He is preaching a sermon, he is instructing, he is wishing people to listen.
"There is clear evidence that he intended to use those words. They were not a slip of the tongue.
"It is a straightforward case."
In court Pastor McConnell's defence lawyer described him as a man of "superlative good character" who helped drug addicts and other "down and outs" that "watery, middle class clergymen" might consider as "untouchables".
Philip Mateer QC argued that although he was "unrepentant" for preaching the gospel, McConnell was sorry for any offence his words may have caused, adding that trust was something to be built up over time.
Earlier, during an appearance in the witness box which lasted more than an hour, McConnell said he never intended to provoke or offend Muslims.
He said: "I had never any intention whatsoever of hurting any one of them and I can say that before the judge and before the almighty God.
"It never entered my head that someone would take me up on that. I was preaching this in the confines of my own church. There are Muslims there who know me and understand me. It never entered my head."
Outside, McConnell expressed relief that the trial had concluded.
He said: "It has been fair. The prosecution has been fair, everybody has been fair.
"I can't wait now to January 5. I want to see the outcome. I want to win."