The sages directed us to express certain convictions and to offer specific praises to G-d Almighty (known as “berachot”, blessings) before and after we perform particular mitzvot. Ramchal says of them later on that those berachot are meant to underscore the significance of the mitzvah we’re about to fulfill, and to thank G-d for giving us the chance to serve Him and perfect ourselves in the process (see 4:9:3 below).
But we recite different berachot before and after saying “Shema Yisroel”, depending on whether we’re saying it in the day- or nighttime, since each one serves its own purpose. In any event, we’ll concentrate on the daytime berachot for “Shema Yisroel” now and go on to the nighttime ones in the next chapter.
The whole thing is rooted in the esoteric fact that G-d reactivates existence each and every day, new-sprung and original. In general He does that so as to preserve it and keep it going for as long as He wants. But there’s a more detailed element to His doing it as well.
We’re taught that each and every day of existence as we know it has its own orders from G-d, its own particular mission. For each day is there to allow for just the right amount of Divine illumination, influence and the like (no more, no less; neither too soon or too late), and in order to facilitate the ultimate perfection . Thus every single day is a fresh and original entity unto itself, a brand new marker in universal renewal.
And this in fact is the central theme of the berachot we recite before the morning “Shema Yisroel”. As such, we reaffirm our belief in this each morning as the process begins for that particular day, and we thank G-d for it.
The first of the two berachot concentrates upon the angelic and higher cosmic spheres, on the stars and constellations, and on their daily and nightly functions all being renewed and reactivated. While the second concentrates upon the role of the Jewish Nation, on G-d’s love for us, and on the function we serve in the grand scheme of things; and it thus serves as an expression of our thanks to G-d for renewing *that* each day. That’s followed by the actual recitation of “Shema Yisroel”, along with everything associated with it we’d cited.
All that culminates in the recitation of the third morning beracha which follows the “Shema Yisroel” itself. That one focuses upon all the great miracles G-d has wrought for us, most especially the exodus from Egypt, which epitomized the renewal of the Jewish Nation and played so significant a role in forging our a mission in this world.