There is need of only one thing

"The Lord said to her in reply, “Martha, Martha, you are anxious and worried about many things.
There is need of only one thing. Mary has chosen the better part and it will not be taken from her.”

Like Martha, we are anxious and worried about many things:  health, family, money, job, tools/property, food and future.
But Jesus says:  Only one thing is necessary.
What is the one thing that is necessary?
"But seek first the kingdom (of God) and his righteousness, and all these things will be given you besides."  (Matthew 6: 33)

The kingdom of God is the reign and authority of Jesus Christ.  Mary, through the inspiration of the Holy Spirit understood that where Jesus is, there is the kingdom.

"LORD, my allotted portion and my cup,
you have made my destiny secure.
Pleasant places were measured out for me;
fair to me indeed is my inheritance."  (Psalm 16: 5 - 6)

Mary chose Jesus and His kingdom as her allotted portion and cup.