— from Dallas Willard: 
Every person should have regular periods in life when he or she has nothing to do. Periods of solitude and silence are excellent practices for helping us learn how to do that. The law that God has given for our benefit tells us that one-seventh of our time should be devoted to doing nothing—no work, not by ourselves or any of our family, employees, or animals. That includes, of course, religious work. This is Sabbath.

What do you do in solitude or silence? Well, so far as things to "get done," nothing at all. As long as you are doing "things to get done," you have not broken human contact. So don't go into solitude and silence with a list. Can we enjoy things in solitude and silence? Yes, but don’t try to. Just be there. Don’t try to get God to do anything. Just be there. He will find you.

Even lay aside your ideas as to what solitude and silence are supposed to accomplish in your spiritual growth. You will discover incredibly good things. One is that we have a soul. Another, that God is near and the universe is brimming with goodness. Another, that others aren’t as bad as we often think. But don’t try to discover these, or you won’t. You’ll just be busy and find more of your own doings.

The cure for too-much-to-do is solitude and silence, for there we find that we are safely more than what we do. Thus, the cure of loneliness is solitude and silence, for there we also discover in how many ways we are never alone. When we go into solitude and silence, we need to be relatively comfortable. Don’t be a hero in this or in any spiritual discipline. You will need rest. Sleep until you wake up truly refreshed. And you will need to stay there long enough for the inner being to become different. Muddy water becomes clear only if we let it be still for a while.

You will know that this finding of soul and God is happening by an increased sense of who you are and a lessening of the feeling that you have to do this, that, and the other thing that befalls your lot in life. That harassing, hovering feeling of "have to" largely comes from the vacuum in our soul, where we ought to be at home with our Father in his kingdom. As the vacuum is rightly filled, we will increasingly know that we do not have to do many of those things—not even those we might want to do.

Excerpted from Renewing the Christian Mind: Essays, Interviews, and Talks by Dallas Willard.

...from John Ortberg:

I find it helpful to think about solitude in two categories. We need brief periods of solitude on a regular basis— preferably each day, even at intervals during the day. But we also need, at great intervals, extended periods of solitude — half a day, a day, or a few days.

We may want to begin a particular day by praying over the day’s schedule — meetings to attend, tasks to perform, people we will be with— and placing it in God’s hands. Through the day we could take five-minute breaks if that is possible, close the door to the office, and remind ourselves that one day the office and the building will be gone — but we will still belong to God.

Ortberg, John. The Life You've Always Wanted: Spiritual Disciplines for Ordinary People (p. 87). Zondervan. Kindle Edition.

The LORD is my shepherd, I lack nothing.
     He makes me lie down in green pastures,
he leads me beside quiet waters,
     he refreshes my soul. (Psalms 23:1–3)

Do you remember Psalm 23? God’s care for his people is first and foremost his presence with his people. That presence refreshes and restores the deepest part of us — our soul. We are better able to experience his presence lying down in green pastures, or beside still waters. Work and relationships drain us; we need time with God. We need rest.

“Most of us are more tired than we know at the soul level. We are teetering on the brink of dangerous exhaustion, and we cannot do anything else until we have gotten some rest.” ― Ruth Haley Barton, Sacred Rhythms: Arranging Our Lives for Spiritual Transformation

It’s not just work that drains us, and it’s not just the pace of our lives. Relationships can drain us, too. You are almost certainly related to or involved with some “high maintenance” people. Solitude and silence are the green pastures and still waters that restore us. 

You’re tired. Your Shepherd is waiting to lead you to a quiet spot. 

Lord, I’m ready for rest but feel too busy. Lead me where I need to go. Amen.