God reveals himself in many ways.
In times past, in the Biblical times, God speaks to the Patriarchs, Abraham, Isaac and Jacob, and promises to be God with them. God also spoke through the prophets to the people. Some of the main prophets of the Old Testament were Ezekiel, Jeremiah, Isaiah, Amos and Micah.
In times past, in the Qur'an, God reveals himself to the prophet Mohammed, and dictates the Qur'an to Mohammed.
In the times of Jesus, God revealed himself through the teachings, the healings and the works of Jesus. God also revealed himself as almighty, with power over life and death, in raising Jesus from the dead, the Resurrection.
In Hinduism, God revealed himself through the Vedas, scriptures which have no human author; rather, they are s'ruti, (that which is heard) by the great rishis and spirtual teachers in the past, in Hinduism.
In Buddhism, God revealed himself by granting enlightenment to the Buddha, who passed on the teachings of his experience; the middle way.
In ancient Mesoamerican religion of the American Indians, God revealed himself as the Great Spirit, Grandfather, the source of all life.
In the Australian Aboriginal religions, (the Dreamtime) God revealed himself as Baiame or Wollumbin, or as Rainbow Serpent, the creator who made the lands, and all the peoples and all the animals.
The list could go on and on, for there are as many religions as there are cultures and societies. That says something about God, no?
However, God reveals himself today, for he is resident in every heart, and awaits your turning to Him and discovery of him, right there. If you ask God for proof of his existence and presence, then ask with sincerity and love; God will not deny. Above all, turn to God with love for God; you will know his presence by his love.