A Google search reveals that the saying "God helps those who help themselves" is not from the Holy Bible. A computerized Bible search corroborates this. Since God instructs us to "Prove all things; hold fast that which is good" (I Thessalonians 5:21) it benefits us to consider to what extent the saying is harmonious with God's Word.
As an overall message, it is not particularly in alignment, as throughout the Bible it is much more emphasized that God helps those who help others.
And the LORD turned the captivity of Job, when he prayed for his friends: also the LORD gave Job twice as much as he had before. Job 42:10
And God is able to make all grace abound toward you; that ye, always having all sufficiency in all things, may abound to every good work: II Corinthians 9:8
Despite its lack of overall harmony, the words "God helps" are a reminder to the Biblically-minded that God's help and backing are available and the primary help we need when confronted with a challenge. Likewise, the words "help themselves" can be a reminder to those knowledgeable of God's Word that while others may offer words of encouragement, there are certain responsibilities that God expects the individual himself to accomplish.
Jesus said unto him, If thou canst believe, all things are possible to him that believeth. Mark 9:23
Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling. Philippians 2:12
An alternative saying, "You do your best, and God will do the rest" fits harmoniously with the truths of God's Word, and offers both encouragement and perspective.