Matthew Henry Whole Commentary:
Care is a burden; it makes the heart stoop (Prov. 12:25); we must cast it upon God by faith and prayer, commit our way and works to him; let him do as seemeth him good, and we will be satisfied. To cast our burden upon God is to stay ourselves on his providence and promise, and to be very easy in the assurance that all shall work for good. If we do so, it is promised,
1. That he will sustain us, both support and supply us, will himself carry us in the arms of his power, as the nurse carries the sucking-child, will strengthen our spirits so by his Spirit as that they shall sustain the infirmity. He has not promised to free us immediately from that trouble which gives rise to our cares and fears; but he will provide that we be not tempted above what we are able, and that we shall be able according as we are tempted.
2. That he will never suffer the righteous to be moved, to be so shaken by any troubles as to quit either their duty to God or their comfort in him. However, he will not suffer them to be moved for ever (as some read it); though they fall, they shall not be utterly cast down.Henry, M. (1994). Matthew Henry’s commentary on the whole Bible: complete and unabridged in one volume (p. 823). Peabody: Hendrickson.
If you are in Christ, the Lord will provide for you, He will be with you in trials, He will use you for His glory- and your good. Depend on these truths. Cling to them.