Which is as a bridegroom coming out of his chamber, and rejoiceth as a strong man to run a race. Which is as a bridegroom, etc. - This is a reference to the rising of the sun, as the following verse is to the setting. He makes his appearance above the horizon with splendor and majesty; every creature seems to rejoice at his approach; and during the whole of his course, through his whole circuit, his apparent revolution from east to west, and from one tropic to the same again, no part of the earth is deprived of its proper proportion of light and heat. The sun is compared to a bridegroom in his ornaments, because of the glory and splendour of his rays; and to a giant or strong man running a race, because of the power of his light and heat. The apparent motion of the sun, in his diurnal and annual progress, are here both referred to. Yet both of these have been demonstrated to be mere appearances. The sun's diurnal motion arises from the earth's rotation on its axis from west to east in twenty-three hours, fifty-six minutes, and four seconds, the mean or equal time which elapses between the two consecutive meridian-transits of the same fixed star. But on account of the sun's apparent ecliptic motion in the same direction, the earth must make about the three hundred and sixty-fifth part of a second revolution on its axis before any given point of the earth's surface can be again brought into the same direction with the sun as before: so that the length of a natural day is twenty-four hours at a mean rate. The apparent revolution of the sun through the twelve constellations of the zodiac in a sidereal year, is caused by the earth's making one complete revolution in its orbit in the same time. And as the earth's axis makes an angle with the axis of the ecliptic of about twenty-three degrees and twenty eight minutes, and always maintains its parallelism, i.e., is always directed to the same point of the starry firmament; from these circumstances are produced the regular change of the seasons, and continually differing lengths of the days and nights in all parts of the terraqueous globe, except at the poles and on the equator. When we say that the earth's axis is always directed to the same point of the heavens, we mean to be understood only in a general sense; for, owing to a very slow deviation of the terrestrial axis from its parallelism, named the precession of the equinoctial points, which becomes sensible in the lapse of some years, and which did not escape the observation of the ancient astronomers, who clearly perceived that it was occasioned by a slow revolution of the celestial poles around the poles of the ecliptic, the complete revolution of the earth in its orbit is longer than the natural year, or the earth's tropical revolution, by a little more than twenty minutes; so that in twenty-five thousand seven hundred and sixtythree entire terrestrial revolutions round the sun, the seasons will be renewed twenty-five thousand seven hundred and sixty-four times. And in half this period of twelve thousand eight hundred and eighty-two natural years, the points which are now the north and south poles of the heavens, around which the whole starry firmament appears to revolve, will describe circles about the then north and south poles of the heavens, the semi-diameters of which will be upwards of forty-seven degrees.
Coming out of his chamber - מחפתו mechuppatho, from under his veil. It was a sort of canopy erected on four poles, which four Jews held over the bridegroom's head.