What's the problem with Christmas and Easter?
Observing either is by the tradition of the the Catholic church. There are no commands, there are a couple of references though...
Jer 10:2 Thus saith the LORD, Learn not the way of the heathen, and be not dismayed at the signs of heaven; for the heathen are dismayed at them.
Jer 10:3 For the customs of the people are vain: for one cutteth a tree out of the forest, the work of the hands of the workman, with the axe.
Jer 10:4 They deck it with silver and with gold; they fasten it with nails and with hammers, that it move not.
Jer 10:5 They are upright as the palm tree, but speak not: they must needs be borne, because they cannot go. Be not afraid of them; for they cannot do evil, neither also is it in them to do good.
Eze 8:13 He said also unto me, Turn thee yet again, and thou shalt see greater abominations that they do.
Eze 8:14 Then he brought me to the door of the gate of the LORD'S house which was toward the north; and, behold, there sat women weeping for Tammuz.
Eze 8:15 Then said he unto me, Hast thou seen this, O son of man? turn thee yet again, and thou shalt see greater abominations than these.
Eze 8:16 And he brought me into the inner court of the LORD'S house, and, behold, at the door of the temple of the LORD, between the porch and the altar, were about five and twenty men, with their backs toward the temple of the LORD, and their faces toward the east; and they worshipped the sun toward the east.
You might take a look at this...
http://www.newadvent.org/cathen/05228a.htm
The Catholic Encyclopedia and the Quarto Decimani