Readers of the Old Testament are often impressed by the absolute assurance with which the prophets acknowledged and experienced the presence of God in their lives. They knew God as a reality.
Consider the many instances when Moses demonstrated God's provision and protection for the children of Israel as he led them through the desert, safely through the Red Sea, securing daily food and drink on their long journey. Despite all their complaints, Moses' followers knew he communed directly with God. Later, the healing works of Elijah and Elisha left their compatriots in no doubt that these holy men communed with God and trusted divine providence for their source of daily blessings.
These deep spiritual thinkers and doers persistently exhorted their followers to seek out and experience God's presence in their lives as well. The Bible abounds with teachings urging readers to exchange a material, limited perception of reality for a spiritual one. Isaiah, for instance, urged his listeners to "Arise, shine; for thy light is come, and the glory of the Lord is risen upon thee. ... Lift up thine eyes round about, and see" (Isa. 60:1, 4).