Hasn't Allah Almighty said, through His Prophet: "Give the laborer his wages before his sweat dries"? Does this mean that Allah gives us our rewards before our sweat dries, and can we feel that reward after every good deed we perform?

The one who said: "Give the hired worker his wages before his sweat dries" is the Prophet, peace and blessings be upon him. This hadith applies to the creation, not the Creator. For Allah, the Exalted, accepts the deeds of whomever He wills and rejects the deeds of whomever He wills. He gives and withholds by His grace and justice. Allah Almighty said: "Whoever desires the immediate—We hasten for him therein what We will to whom We intend."