Matthew 6:33

31 Therefore take no thought, saying, What shall we eat? or, What shall we drink? or, Wherewithal shall we be clothed?
32 (For after all these things do the Gentiles seek:) for your heavenly Father knoweth that ye have need of all these things.
33 But seek ye first the kingdom of God, and his righteousness; and all these things shall be added unto you.
34 Take therefore no thought for the morrow: for the morrow shall take thought for the things of itself. Sufficient unto the day is the evil thereof.

In Plain English

Do not worry about what you need to live
God knows what you need to live and serve Him
Seek Him and His purposes and all you need to do these will be provided by Him
Do not worry about tomorrow as you have enough problems to deal with each day.

The Principles in Matthew 6:33

As you seek the:

Purposes of The Kingdom of God (God's Will for you as a result of your place in The Kingdom)
And the furthering of the relationship you have with Jesus and The Father
All you need to live in the way God require you to live will be provided by Him
All the promises made by God to you will be fulfilled and you will matured by God into the image of Jesus

How do you keep Matthew 6:33

Obedience to God in the things He asks you to do each day will ensure you observe the requirements of Mat 6:33

This is how you 'work out your salvation'.

As you focus on your relationship with Jesus and the purposes of His Kingdom in all you do you keep your salvation.

Comment on Matthew 6:33

God has prepared you life path from before creation for you to walk in and develop in the way He desires you to mature and develop.

As you walk in the principles of Mat 6:33 you walk this path and all God has for you and desires for you is on this path.

All that God has promised for you or prophesied to you will be on this Mat 6:33 path