Since on the seventh day God was finished with the work he had been doing, he rested on the seventh day from all the work he had undertaken. So God blessed the seventh day and made it holy, because on it he rested from all the work he had done in creation." Genesis 2:2-3
If you read the above passage only in a strict literal sense you would do two things: 1) make God out to be less than He really is. The word "rested" is of course silly when applied to a Being who is beyond the realm of matter. 2) You would miss what is really being said here: the passage contrasts the difference between creating and not-creating. Creating is done strictly by God, He literally "created" the universe out of nothing. We humans do not have anything comparable to that since all our personal creating has to start with something - a painter; paint, a potter; clay, even a philosopher starts with an idea. Another point to remember is that God is outside the realm of time. The author who is divinely inspired by God, but a human being can only describe the events in a sequence because we humans live within the realm of time. Time is the measurement of change - thus the author writes creation takes place over a week - 6 days to be precise and on the 7th day, God is not creating.(when we are not working, we are resting).
So what is the point here? God contrasts creating and not creating by declaring that when He is not creating we are to consider that time Holy. Holy not because of anything man has done but Holy because everything that God did. Thus we humans, in our task of creating, (we are co-creators in human life)that is living our lives, describe this time as work (not just in the sense of Capitalistic work of producing). We are engaged in human things, things that are done for man by man. The word for that is "liturgy" (translates to people's work or public works). All things beyond (the non-creating by God) are Holy and thus man has a choice - continue the work of man or join God in His work, His liturgy, which is the ultimate reason God created us. We call this worship - and as Catholics there is the Mass. The Liturgy of the Word (Sacred Scripture -God's Word) and the Liturgy of the Eucharist - God's gift to humanity, His only begotten Son, The Word Incarnate, the body, blood, soul, and divinity of Jesus. In my humble opinion our understanding of life can only be truly appreciated if we see ourselves in relationship with God the Creator. He is the Creator and we are the created.