Here the Apostle's exhortation has in view the circumstances of life. He is not unmindful that, in a world of sorrow and sickness, of want and care, there will be trials to face and burdens to be borne; but, he would not have us racking our poor hearts with them. He, himself, writes from a prison, and had suffered want, and a companion and fellow-laborer had been sick, nigh unto death; but in these sorrowful circumstances he had been lifted above all anxious care, and therefore can say to others, "Be careful for nothing."
We may have to face trials in our families, trials in our businesses, trials amongst the Lord's people; sorrows from sickness, sorrows from want, sorrows from the saints, that press upon us as a great burden and, as one has said, "How often a burden possesses a person's mind, and when he tries in vain to cast it off, it comes back and worries him."
How then can we find relief? How is it possible to "Be careful for nothing"? Very blessedly the Apostle unfolds the way to be free, not necessarily of the trial, but of the burden of the trial, so that it no longer weighs the spirit down with care and anxiety. He says, "In every thing by prayer and supplication with thanksgiving let your requests be made known unto God." Thus only shall we find relief. "In every thing," whatever the trial may be, small or great, make it known to God in prayer; and tell God exactly what you wish, "let your requests be made known” to Him. The requests may not be for our good, they may not be according to the mind of God; they may even be foolish, but we are to make them known to God.
What will be the result? Will He answer the requests? Will He remove the trial? He may see that to answer the request, or remove the trial would not be for our good. So far as the immediate trial is concerned, He will act in perfect wisdom for our good, according to His perfect love. But this God will do; He will relieve our hearts from the burden of the trial. If we pour out our hearts before Him, He will pour in His peace into our hearts – that peace of God which passeth all understanding.
So Hannah found, in the days of old, when, in her sore trial she could say, "I ... have poured out my soul before the Lord." In result, we read, "Her countenance was no more sad." And yet, at the time, her circumstances were just the same. Afterward, indeed, the Lord changed her circumstances, but first He showed that He had the power to change Hannah. From grief of heart and bitterness of soul, she was brought into great peace – the peace of God which passeth all understanding – through making known her requests to God (1 Sam. 1:6-18).