The way first century Jews viewed time was intricately connected with the way they understood the Sabbath:
"When God made the world, he "rested" on the seventh day...It means that in the previous six days God was making a world--heaven and earth together--for his own use. Like someone building a home, God finished the job and then went in to take up residence, to enjoy what he had built. Creation was itself a temple, the Temple, the heaven-and-earth structure build for God to live in. And the seventh-day "rest" was therefore a sign pointing forward into successive ages of time, a forward-looking signpost that said that one day, when God's purposes for creation were accomplished, there would be a moment of ultimate completion, a moment when the work would finally be done, and God, with his people, would take his rest, would enjoy what he had accomplished." -N. T. Wright, Simply Jesus
As this was the case, the sabbath was the natural day to celebrate, to worship, to pray, to study God's law. It was the moment in which the progression of history from its foundations to its ultimate resolution was fully sensed.
Now let's look at how Matthew structures the geneology of Jesus. Matthew arranges the geneology in 3 groups of 14 (six 7s), emphasizing Jesus appearing at the start of the sabbath-of-sabbaths, the seven-times-seventh year--the year of jubilee when slaves would be freed, debts cancelled, and life would get back on track (see Leviticus 25).
"Now, and only now, do we see what Jesus meant when he said the time is fulfilled. That was part of his announcement right at the start of his public career (Mark 1:15). Only this, I believe, will enable us to understand his extraordinary behavior immediately afterwards. He seems to have gone out of his way to flout the normal sabbath regulations. Most people in the modern church have imagined that this was because the sabbath had become "legalistic," a kind of observance designed to boost one's sense of moral achievement, and that Jesus had come to sweep all that away in a burst of libertarian, antilegalistic enthusiasm. That, though commonplace, is a trivial misunderstanding. It is too "modern" by half. Rather, the sabbath was the regular signpost pointing forward to God's promised future, and Jesus was announcing that the future to which the signpost had been pointing had now arrived in the present. In his own career...The time was fulfilled, and God's kingdom was arriving.
In particular, Jesus came to Nazareth and announced the jubilee. This was the time--and time!--when all the sevens, all the sabbaths, would rush together. This was the moment Israel and the world had been waiting for...You don't need the sabbath when the time is fulfilled. It was completely consistent with Jesus's vision of his own vocation that he would do things that said, again and again from one angle after another, that the time had arrived, that the future, the new creation, was already here, and that one no longer needed the sabbath. The sabbath law was not, then, a stupid rule that could now be abolished (though some of the detailed sabbath regulations, as Jesus pointed out, had led to absurd extremes, so that you were allowed to pull a donkey out of a well on the sabbath, but not to heal the sick). It was a signpost whose purpose had now been accomplished. It was a marker of time pointing forward to the time when time would be fulfilled; and that was now happening." -N. T. Wright, Simply Jesus
