Rest in the Lord by knowing Him;
Know Him by loving Him;
Love Him by obeying Him.
He will take care of everything else.
Sometimes it doesn’t feel that way, because He is more interested in spiritual growth than physical comfort. He knew we would question His ways so He wrote it in His Word:
Jeremiah 29:11 For I know the thoughts that I think toward you, saith the LORD, thoughts of peace, and not of evil, to give you an expected end.
Isaiah 55:9 For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts.
Trust Him to sanctify you to do His good pleasure.
After all, He created the very environment in which you live:
And He is the One who will judge it.
Matthew 11:28 Come unto me, all ye that labour and are heavy laden, and I will give you rest.
Mark 12:30 And thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength: this is the first commandment.
John 15:10 If ye keep my commandments, ye shall abide in my love; even as I have kept my Father’s commandments, and abide in his love.
Philippians 2:13 For it is God which worketh in you both to will and to do of his good pleasure.
John 17:17 Sanctify them through thy truth: thy word is truth.
Hebrews 12:23 To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,