Wait! Wait! Let your waiting be on the Lord! He is worth waiting for. He never disappoints the waiting soul.
While waiting keep up your spirits, Expect a great deliverance, and be ready to praise God for it.
The promise which should cheer you is in the middle of the verse — “He shall strengthen thine heart.” This goes at once to the place where you need help. If the heart be sound, all the rest of the system will work well. The heart wants calming and cheering, and both of these will come if it be strengthened. A forceful heart rests and rejoices and throbs force into the whole man.
No one else can get at that secret urn of life, the heart, so as to pour strength into it. He alone who made it can make it strong. God is full of strength, and, therefore, He can impart it to those who need it. Oh, be brave; for the Lord will impart His strength to you, and you shall be calm in tempest and glad in sorrow.
He who penned these lines can write as David did — “Wait, I say, on the Lord.” I do, indeed, say it. I know by long and deep experience that it is good for me to wait upon the Lord.
[from Faith’s Checkbook by Charles H. Spurgeon]