We talk of the year having fifty two weeks, although, in reality, a year is one day and six hours longer than that. When all these discrepancies of 30 hours are added together, it comes out that only once in 28 years, the sun is at exactly the same place in the sky, at the same hour and on the same day of the week, that it was at the time of its creation. We mark this occasion in the month of Nissan by rising at dawn to make the Bircas HaChama - the blessing on the sun. After the morning prayers are recited, everyone goes outside and recites with great simcha. This is accompanied by the singing of songs and praises.
Freedom is something only a slave can really appreciate.
Only someone who emerges from the darkness to the light can really have any idea of what light is. Had the Jewish People never been enslaved in Egypt, we would never have experienced the true freedom that we commemorate on the festival of Pesach. In our long history, in times of the greatest darkness, when we have emerged, it has been to the greatest light. Our era has seen some of the darkest nights of our history. G-d has promised us that, exactly when the night is darkest, He will bring the final redemption.