How can you prove that the Bible doesn't teach God helps those who help themselves? Doesn't the Bible condemn being lazy?
Indeed it would be difficult to prove that the Bible doesn't teach that God helps those who help themselves. Certainly it does teach man's responsibility to work.
Even from the beginning man was created to work. "And the LORD God took the man, and put him into the garden of Eden to dress it and to keep it." (Gen 2:15) In the New Testament Paul lays down the rule, "if any would not work, neither should he eat." (2 Thes 3:10) Paul also said, "I can do all things through Christ who strengthens me." (Phil 4:13) Indeed, in another sense we are told to "work out your own salvation with fear and trembling." (Phil 2:12)
On the other hand, I find the phrase "God helps those who help themselves" to be questionable in a couple of ways. Not in the statement itself, but in its results.
First of all, I think it rather too broad a statement. The scripture indicates that God helps those who are His. "And we know that all things work together for good to them that love God, to them who are the called according to his purpose." (Rom 8:28) This passage says that God helps those who love and obey him, but does not promise that help to those who would reject him. David recognized the same thing when he said "And the LORD shall help them, and deliver them: he shall deliver them from the wicked, and save them, because they trust in him." (Ps 37:40) In this light I would modify the old saying, to phrase it "God helps those who help themselves by trusting and obeying Him."
The other problem I have with the statement is that it makes it easy to push God out of the picture. If God helps those who help themselves, how much of what I accomplish is through my own effort, and how much through God's? Could I not say that I did most of the work, and God did just a little? From that there is but a short step to "God, I'll tell you when I need your help, but I can handle most, if not all, things myself." Part of Paul's argument in Romans 8 is that man could not do anything pertaining to salvation by himself. If it were so, then Jesus need not have died. (The same argument is made in the book of Hebrews.) So God indeed helps those who help themselves, but it is more like 99% on God's part and 1% on man's part. The grace of God can be pictured like a man standing at the foot of the Sears Tower in Chicago. Hard as he tries, he can only jump perhaps three feet high, but God's grace takes him from three feet above the sidewalk to the top of the tower. There is only so much we can do, and God does the rest.