Now, with this in consideration, it's not shocking that people would worship the sun—the warm sunny days of the summer are bright, while the dark dreary days of the winter are more morbid. As such, a celebration of the winter solstice was bound to develop. The winter solstice signifies the shortest day of the year, thus marking the lengthening of the days and the shortening of the darkness (at least in the Northern Hemisphere).[1]

As such, this was celebrated with candles and light (they didn't have light bulbs or electricity back then). The sight of these lights reminded sun-worshipers of the coming sunlight—a rebirth of the sun, if you will—and made them content. They countered the dreariness of the season with feasts and festivities. Today, we still do the same.

As a person who is undiagnosed, but likely suffers from Seasonal Affective Disorder, I completely see the connection of the lights and decorations lifting your mood. The devil knows our weaknesses, and he wants to exploit them for his war against God. He sees that we get a little anxious and down doing the winter, so he dangles false glimmers of hope before us to distract us from the real Light of our world.

Christmas trees, decorations, and lights are all distractions that remain from the pagan holidays like Saturnalia and Yule.

The evidence of our participation in the pagan sun festivities instead of the birth of Jesus as we claim, is that we put up lights and begin decorating before December 25—note that the winter solstice is usually between December 21-23. We take the decorations down right after December 25. Doesn't this seem backwards? A true celebration of Jesus would begin on His birthday and continue a few days after (like the 12 days of Christmas, from the alleged date of His birth to the alleged date of the wise men's arrival—see