The present paper carries out a corpus linguistic analysis of the first debate of 2019 Indonesia presidential election. The study compared the speech of presidential candidate pair number 1, JW and MA, and number 2, PS and SSU, in the debate in terms of lexical diversity and linguistic features. The research employs a mixed-method research design by using two corpus technical analyses, i.e. type/token ratio and keywords. Results show that PS spoke the most, while MA spoke with the most varied vocabulary. The study also found that foreign words from Arabic in the keywords of JW, PS, and SSU are generally used to show their belief as well as to embrace the Indonesian Muslim communities. However, the Arabic words used by MA tend to show his identity as a Muslim cleric, reflecting his in-depth understanding of Islam. Unlike the Arabic word usage, foreign words from English are used more for a practical reason and to emphasize arguments, particularly by JW and PS. Additionally, the study reveals that from the lexical word-class distribution, JW tends to give more focused information and entities, while PS tends to offer more explanations to present information. All things considered, the present writers argue that corpus linguistics is an essential method to investigate actual patterns of language used by politicians to interpret further. All in all, the present research is supposed to give a methodological contribution to the study discussing the relation between language and politics.