Lord Of The Sabbath- What Did Jesus Mean Here?

Mark 2:23-24,27-28

[23]Now it happened that He went through the grainfields on the Sabbath; and as they went His disciples began to pluck the heads of grain.

[24]And the Pharisees said to Him, “Look, why do they do what is not lawful on the Sabbath?”

[27]And He said to them, “The Sabbath was made for man, and not man for the Sabbath.

[28]Therefore the Son of Man is also Lord of the Sabbath.”

What did Jesus mean by this? Thank you

source http://www.nairaland.com/6304169/lord-sabbath-what-did-jesus-mean