Sometimes, we need to be reminded to lie down. We also need to rest. In Psalm 23, we learn that our Good Shepherd makes us "lie down in green pastures" and leads us "beside the still waters". He knows that we need the calm and rest that these provide, even when we don't realize it ourselves.
Our bodies are designed to have regular rest. God Himself rested on the seventh day after His work of creation (Gen. 2:2-3; Ex. 20:9-11). Jesus knew there was a time to minister to the crowds and a time to rest. He instructed His disciples to "come aside ... and rest a while" (Mark 6:31).
When we rest, we refocus and are refreshed. When we are filling every hour with activity - even with worthwhile things - God often gets our attention by making us "lie down". Rest is a gift - a good gift from our Creator who knows exactly what we need. Praise Him that He sometimes makes us "lie down in green pastures". If we don't come apart and rest awhile, we may just plain come apart. So, have a rest.