The Trinity is biblical and therefore it is not something we "do not know".These six verses for me are spot on and lead me to reject Christianity, even verse 3 where I know you will say that it doesn't apply because Jesus never actually said "Let us go after other gods which you have not known, and let us worship them," and he was probably talking about Jehova (though he only said my/our Father), but I read the Tora passage in light of what actually happened in real history where the vast majority of Christians are in effect worshiping/following other gods because they don't observe Jehova's laws and-- especially in the case of Catholic and Orthodox Christians -- they have added observances which clearly fall into the "which you have not known" category such as Trinity, eating pig (which is big in the Bible Belt, even on the Day of Atonement), shellfish, etc.(i.e. the ritual laws), Sunday worship, Mary veneration, communion (drinking Jesus' blood and body), infant baptism, etc..
1.Everything I command you that you shall be careful to do it. You shall neither add to it, nor subtract from it.
2.If there will arise among you a prophet, or a dreamer of a dream, and he gives you a sign or a wonder,
3.and the sign or the wonder of which he spoke to you happens, [and he] says, "Let us go after other gods which you have not known, and let us worship them,"
4.you shall not heed the words of that prophet, or that dreamer of a dream; for the Lord, your God, is testing you, to know whether you really love the Lord, your God, with all your heart and with all your soul.
5.You shall follow the Lord, your God, fear Him, keep His commandments, heed His voice, worship Him, and cleave to Him.
6.And that prophet, or that dreamer of a dream shall be put to death; because he spoke falsehood about the Lord, your God Who brought you out of the land of Egypt, and Who redeemed you from the house of bondage, to lead you astray from the way in which the Lord, your God, commanded you to go; so shall you clear away the evil from your midst. Devarim - Deuteronomy - Chapter 13 (Parshah Re'eh)
(And what is wrong with a Sunday worship?)
The old law was fulfilled by Jesus and therefore no longer has to be kept. So it is no problem to eat pigs.