The emergence of Islamic banks in Indonesia today is increasingly mushrooming. This is inseparable from the role of the number of Muslim populations in Indonesia who want an Islamic economic and banking system that is far from usury. The Islamic banking system has been exemplified by the Prophet Muhammad and his companions in the past and this has become the basis or foundation for the establishment of Islamic banks. But in reality in Indonesia, the relevance of the Islamic banking system is less attractive. This research is a descriptive qualitative research, using library research method. The purpose of this study is to examine the practice of Islamic banking as exemplified at the time of the Prophet Muhammad SAW and to see the relevance and development of Islamic banking practices in Indonesia. The conclusion of this study is that the model of banking services, products and activities exemplified by the Prophet is still used in the Islamic banking system in Indonesia, but in fact there are many Islamic bank practices that deviate and are not in accordance with Sharia rules.

Gadung (Dioscoreahispida Dennst), is a tuber-like plant that grows vines and also climbs with a height of 5-20 m. tuber production from gadung plants can be increased if this plant is cultivated intensively because naturally this plant can grow and develop very well in tropical climates. Gadung tubers have various health benefits and have high economic value. Processed gadung tubers, commonly known as gadung crackers, can become a business opportunity to meet the needs of the community, both from the upper, middle and lower classes. Because these processed products are light and healthy snacks and the price is affordable. This study uses a qualitative approach. The type of research used is library research with the documentation method, namely finding and studying data regarding variables in the form of notes, documents, books, journals and so on. The data sources used are primary and secondary data sources. The data analysis technique used is content analysis method. To test the validity of this research data using a credibility test by increasing persistence, researchers also use source triangulation techniques. Business opportunities in doing business have many indicators that must be recognized and several factors that must be considered so that they can minimize the impact of failure of business opportunities in their business