Psalm 50:15

We can learn a lot about prayer simply by reading Psalm 50:15. It is a summary theology of prayer all by itself. Here is what Charles Spurgeon had to say about it his sermon entitled "Robinson Crusoe's Text" given on August 30, 1885 at the Metropolitan Tabernacle in London:

"Robinson Crusoe has been wrecked. He is left in the desert island all alone.
His case is a very pitiable one. He goes to his bed, and he is smitten with
fever. This fever lasts upon him long, and he has no one to wait upon him—none
even to bring him a drink of cold water. He is ready to perish. He had been
accustomed to sin, and had all the vices of a sailor; but his hard case brought
him to think. He opens a Bible which he finds in his chest, and he lights upon
Psalm 50:15 "Call upon me in the day of trouble: I will deliver you, and you
will glorify me." That night he prayed for the first time in his life, and ever
after there was in him a hope in God, which marked the birth of the heavenly
life."

I would highly reccomend reading the entire sermon which can be found on the Spurgeon Archive here: Robinson Crusoe's Text