One time a man was drowning in a river. He fought, struggled, labored, strained, strove and did his best to the utmost (the whole nine yards) to save himself.
While all this was happening, his friend who was an expert swimmer watched and did nothing. He just looked on and on attentively. The rest, who did not know how to swim, watched helplessly spewing out angry words against the expert swimmer.
"Do something!!! He is drowning!!!"
"Hey! What are you waiting for? The man is drowning!!!"
"What are you doing just standing there?!!?"
After a few moments, the drowning man was gradually losing strength, all efforts to save himself proved futile. Exhaustion began to quickly set in until it completely consumed him...and then he ceased trying to save himself.
With cat-like quickness, it was then that the expert swimmer briskly and nimbly dived to his rescue. Without difficulty, he easily rescued the man, pulling him to safety.
He then explained to the rest: "You see, I was waiting for him to be exhausted. I could not save him if he still struggles to save himself. We would go down and drown together if I attempt to rescue him while he was still very active striving to save himself. He would forcefully grab me all over in the wrong places and bring us down. I must do all the rescuing."
Applying this to spiritual salvation---It is only until we realize that we are helpless and powerless in ourselves to save ourselves that we are ready for the salvation of the Lord Jesus Christ. He must do all the saving.
