Is worshipping Jesus and/or Allah a great sin?

Well, if are monotheistic and follow the Old Testament, then you are Jewish, and you do not recognize either Jesus or Mohammad as divine.

worshipping Jesus and/or Allah would be a great sin for a Jewish person. Or should I say a person whom practices Jewdisum. They only use the Abrahamic books and such, which Christians call the Old testament, A Christian would worship the holy trinity...the father, the son, and the holy spirit

"Allah" is a title, not a name. It's like "dad" or "mum". It's the Arabic equivalent of "God", which is not the name of any god. Muhammad's god is the god of Abraham, Noah, Moses, and Jesus. Christians pretend it's not the same god, as though telling a disagreeable story about George Washington means my George Washington is not the same person as yours.

In the Qur'an, God hammers repeatedly on the point that he has no sons or daughters in general, and Jesus in particular is not his son. There is no such thing as the Trinity, and Jesus is definitely not God himself. If you believe these things about Jesus, or worship him in any way, you will certainly go to hell. So you have to decide which story you want to follow. Same god, different stories.

Also, the Gospel of John, written 70 years after Jesus' crucifixion, is the only Gospel that makes Jesus out to be God. The other Gospels, written decades earlier, make Jesus a man, adopted by God, or a semi-divine being, sired by a god--as so many men were in the days of Jesus. The Apostle Paul, who wrote his epistles many years before the earliest Gospel, makes Jesus a man adopted by God at the resurrection. But a lot of Christians will say that the broad consensus of qualified biblical scholars and historians is a naive misinterpretation, a complete misunderstanding of the bible. Go figure.

Worshiping Jesus is not a sin.

Worshiping Satan/Allah is a sin.

"Allah" is Arabic for God and is used in Arabic translations of the Bible. Abraham did not know God's name but was saved. God reveals Himself progressively throughout time and history as recorded in the Bible, and that includes His triune nature. The Father, the Son, and the Holy Spirit are equally God.

So to answer your question, no.

Peace be with you.

no its not a sin to worship jesus who is god with the father and holy spirit

Yes, just like YHWH, a sin against reality and people

Jesus I know, but who is this Allah impostor guy?

Jesus is God, Allah is God, so the same God, just different views

The god of old times is sstill the god of todays time. God loves us all . and wwants us to only love him. do the commandment during the time of moses and you find the real god.