Do I need to pay tithe?
A pastor said "not paying tithe is robbing God".
Did Paul say we (gentile Christians) must pay tithe in New Testament?
Paul said to follow the Savior, not him. Paul was a mere mortal, just like you and me. He had no authority whatsoever to change a single thing that the Almighty ordained. In fact the Scriptures warn us sternly not to add to, or subtract from, them.
There is a story in the Bible where the Messiah talked about how the Pharisees tithed even their spices. He said they
should have done that, but that they neglected the weightier matters of mercy and justice. Who would Paul be to overwrite the Son of YHWH, aka God?
The biggest problem to me is that you are not seeing that Paul is not our Deity. Again, he was a mere mortal. In fact, He kept the Laws of the Old Testament, contrary to what Christian tradition teaches. For example in Acts 21 we see that he took a Temple vow to show that he kept the Law of Moses. (See the KJV.)
See also these verses:
1 John: 3-4 For sin is the breaking of the Law.
Romans 2:12 - For as many as have sinned without Law will also perish without Law, and as many as have sinned in the Law will be judged by the Law 13 (for not the hearers of the Law [are] just in the sight of YHWH, but the doers of the Law will be justified;
Romans 3:31 - Do we then make void the Law through faith? Certainly not! On the contrary, we establish the Law.
Romans 6:16 - Do you not know that to whom you present yourselves slaves to obey, you are that one's slave whom you obey, whether of sin [leading] to death, or of obedience [leading] to righteousness? [This is clearly saying that sin leads to death, i.e. eternal death. Yes, there is mercy, and there are so many opportunities to turn around, couontless "2nd chanes", but sin still leads to eternal death if we don't take it seriously and take it to the Lord. Not my opinion. It's what the Word says over and over.
These quotes are mostly from Paul whom we are often taught said the law was no longer in effect. Here is another quote from him.
Acts 25:8 Paul denied the charges. “
I am not guilty of any crime against the Jewish laws or the Temple or the Roman government,” he said.
Oh, and we can't say there is one law for Jews like Paul and one law for the rest of us. The Bible never even hints at any such divide. In fact in the Torah we are told that aliens/foreigners are to obey the same Law in Israel as the Israelites, and in the New Testament we are told "There is neither Greek nor Jew."
If you ever want to look into traditions of men which too commonly the Church fosters, I suggest Psalm 119 Ministries videos. Maybe start with The Pauline Paradox. The channel is extremely scholarly, in historical, linguistic and Scriptural ways. Yet they are no way boring and they always say "Test the Scriptures....Test everything." They clear up what seems to be a lot of contradictions in the Bible, like how it seems Paul is saying the Law has been done away with in one case, but supports it in another. Hint: There was more than one kind of Law, just as in our country. In the Bible there is the Mosaic Law, the law of sin and death and so on. At least 7 different uses for "law." Psalm 119 uses their scholarship to show the true intent supported by context and language analysis.
But, again, Paul had no authority to change a single thing spoken by the Almighty and His Son. Further we are told in the Bible that the Creator "changes not." He says what He means and He means what He says. He said His laws are "for all generations."