Prayer becomes trivial when ceasing to be an act in the soul. The essence of prayer is agada, inwardness. Yet it would be a tragic failure not to appreciate what the spirit of  halachah does for it, raising it from the level of the individual act to that of an eternal intercourse between the people Israel and God; from the level of an occasional experience to that of a permanent covenant. It is through halachah that we belong to God not occasionally, intermittently, but essentially, continually. Regularity of prayer is an expression of my belonging to an order, to the covenant between God and Israel, which remains valid regardless of whether I am conscious of it or not. Abraham Joshua Heschel

God is the source of Revelation, but He works through men, whose capacity to grasp the divine truth depends on their personal insight and on the conditions of their age, whose children they inescapably are. Moreover, what men receive they refract through the medium of their own personality. It will always be the Revelation of God, but never the full Revelation; it will be approaching the divine "infnity," but never quite reaching it. Hence, the content of Revelation vouchsafed to men constitutes a growing and evolving body of truth. . . . Not only does Revelation differ in content and depth, varying with the individual, but it is not limited in time. In other words, it is not an event, but a process. After the period of the Patriarchs, to whom God revealed Himself, Sinai marked the commencement, not the conclusion, of Revelation. The theophany on Sinai may be conceived of literally, mystically, or philosophically, but it represents a basic historical fact without which all the subsequent history of Judaism, and indeed, of the Jewish people is inexplicable.

In increasing measure, contemporary Biblical scholarship is recognizing this truth and accepting the historicity of Moses and the Mosaic character of at least a part of the Pentateuch. But scholarly analyses aside, for the Jewish religious consciousness, the first and greatest single hour of Revelation was at Sinai. . . That the Torah is Mosaic in essence is increasingly being recognized among scholars, but the ultimate disposition of this issue does not affect the religious validity of the Revelation which is the Torah's essence. Robert Gordis

Quoted in Or Hadash: A Commentary on Siddur Sim Shalom for Shabbat and Festivals by Reuven Hammer, RA-USCJ 2003