Where is the contradiction between love and jealusy,

No contradiction with the two "different" words you are currently using BUT the Bible uses jealousy in both context and does not clarify that there is a difference. People who will read the bible and see jealousy for both will see the contradiction and may even question (like me) the validity of the Bible or even whether or not since it is inaccurate or the translations lose the original words meaning may not be something they want to base their souls on.

modern usage of "jealousy"

Here is another problem. The language of today does not match accurately with the original texts of the Bible so how can we or anyone depend on it?


since the word used for jealousy does not mean what the modern usage of "jealousy"

What was the word used that you are talking about. I remember the same words being used and not different words.