Question: "Do human beings truly have a free will?"
Answer: If "free will" means that God gives humans the opportunity to make choices that genuinely affect their destiny, then yes, human beings do have a free will. The world's current sinful state is directly linked to choices made by Adam and Eve. God created mankind in His own image, and that included the ability to choose.
However, free will does not mean that mankind can do anything he pleases. Our choices are limited to what is in keeping with our nature. For example, a man may choose to walk across a bridge or not to walk across it; what he may not choose is to fly over the bridge—his nature prevents him from flying. In a similar way, a man cannot choose to make himself righteous—his (sin) nature prevents him from canceling his guilt (Romans 3:23). So, free will is limited by nature.
This limitation does not mitigate our accountability. The Bible is clear that we not only have the ability to choose, we also have the responsibility to choose wisely. In the Old Testament, God chose a nation (Israel), but individuals within that nation still bore an obligation to choose obedience to God. And individuals outside of Israel were able to choose to believe and follow God as well (e.g., Ruth and Rahab).
In the New Testament, sinners are commanded over and over to "repent" and "believe" (Matthew 3:2; 4:17; Acts 3:19; 1 John 3:23). Every call to repent is a call to choose. The command to believe assumes that the hearer can choose to obey the command.
Jesus identified the problem of some unbelievers when He told them, "You refuse to come to me to have life" (John 5:40). Clearly, they could have come if they wanted to; their problem was they chose not to. "A man reaps what he sows" (Galatians 6:7), and those who are outside of salvation are "without excuse" (Romans 1:20-21).
But how can man, limited by a sin nature, ever choose what is good? It is only through the grace and power of God that free will truly becomes "free" in the sense of being able to choose salvation (John 15:16). It is the Holy Spirit who works in and through a person's will to regenerate that person (John 1:12-13) and give him/her a new nature "created to be like God in true righteousness and holiness" (Ephesians 4:24). Salvation is God's work. At the same time, our motives, desires, and actions are voluntary, and we are rightly held responsible for them.