Some time ago, on the coast of the Isle of Wight, a woman thought she heard in the midst of the howling tempest the voice of a man. She listened. She strained her ear again, and she caught, amid the crack of the blast and the thundering of the winds, another cry for help.
Three poor mariners
She ran at once to the beachmen, who launched their boat, and some three poor mariners who were clinging to the mast were saved.
Had that cry been but once, and not again ... either she might have doubted as to whether she had heard it at all, or else she would have drawn the melancholy conclusion that they had been swept into the watery waste, and that help would have come too late.
Continue in prayer!
So when a man prays but once, either we may think that he cries not at all. Or else that his desires are swallowed up in the wild waste of his sins, and he himself is sucked down into the vortex of destruction. So, continue in prayer!
Source: C. H. Spurgeon