Studying World Religions
First focus on understanding Islam correctly. Otherwise its very easy to get confused while reading other scriptures. For starters you can watch these videos. Later you can read books written on theology from various scholars. https://www.youtube.com/playlist?list=PLh9mgdi4rNeyuvTEbD-Ei0JdMUujXfyWi https://www.youtube.com/watch?v=PgyGweq_DRM&list=PLdLiRaajwSXTiyMxz9Imt9TBZhwCPk7k_