My 10-year-old son has had a hard past. We, his parents, fought the first seven years of marriage; however, now we are in the process of planting new godly seeds into him. But now we are having to deal with the seeds of disobedience, disrespect, and complaining. We want to uproot the bad seeds and plant and nourish good seeds of obedience, respect, and gratefulness.
I thank you in advance for your help.
Consistency is the key. Both consistency in your expectations of his doing what is right and your own consistency in setting a good example of how to properly behave. Though you are starting a bit late, read through all the information on raising children -- even for the years that before your son's age -- to see the things you need to do. See: Raising Godly Children in a Wicked World.