عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ رَضِيَ اللَّهُ عَنْهُمَا أَنَّهُ سَمِعَ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ عَامَ الْفَتْحِ وَهُوَ بِمَكَّةَ إِنَّ اللَّهَ وَرَسُولَهُ حَرَّمَ بَيْعَ الْخَمْرِ وَالْمَيْتَةِ وَالْخِنْزِيرِ وَالْأَصْنَامِ فَقِيلَ يَا رَسُولَ اللَّهِ أَرَأَيْتَ شُحُومَ الْمَيْتَةِ فَإِنَّهَا يُطْلَى بِهَا السُّفُنُ وَيُدْهَنُ بِهَا الْجُلُودُ وَيَسْتَصْبِحُ بِهَا النَّاسُ فَقَالَ لَا هُوَ حَرَامٌ ثُمَّ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عِنْدَ ذَلِكَ قَاتَلَ اللَّهُ الْيَهُودَ إِنَّ اللَّهَ لَمَّا حَرَّمَ شُحُومَهَا جَمَلُوهُ ثُمَّ بَاعُوهُ فَأَكَلُوا ثَمَنَهُ.

(رواه البخاري)

 Jaabir Bin Abdullah (may Allah be pleased with him) has narrated that he heard the Prophet (may peace and blessings be upon him) saying on the year of the conquest (of Makkah) and He (may peace and blessings be upon him) was at Makkah:
“Verily Allah and His Messenger (peace and blessings be upon him) has made the trading of alcohol, carrion, swine and idols totally unlawful.” So it was said: “Oh Messenger of Allah, what about the fat of carrion, for certainly it is used as a coating and overlay for the boats, it is used to grease and anoint the leather and people also carry it along with them.” The Prophet (may peace and blessings be upon him) said: “No! It is unlawful!” Then the Prophet (may peace and blessings be upon him) said at that point: “Allah destroy the Jews (May Allah damn them), certainly when Allah made the fat unlawful they beatified it, then sold it, then ate from it’s price (profit).”
Bukhari # 2236
This narration shows the importance of staying away from those things that have been made unlawful for us. Furthermore, is deriving benefit and even trading of any thing that is haram.
On account of this, Allah cursed the Jews. They didn’t only perpetrate the commandments of Allah but they went to the extent of doing exactly what they were commanded not to do.
We often see that one may tend to justify sins on account of one’s own ideology and understanding. In his eyes he only sees the benefit and he is blind to the harms of it.  What about when our Creator who knows what’s best for us, commands us to do something or stay away from something?
Unfortunate indeed is when we find ourselves in the same dilemma. Whatever has been made haram for us is indeed harmful for us, thus the benefit that maybe derived from it is far lesser than the harms.
May Allah protect us and guide us. Ameen