Take Colossians 3:18-4:1 for example. I count at least seven distinct commands, each with one or more attending motivations.
Command: Wives, submit to your husbands.
Motivation: As is fitting in the Lord.
Given all that is true of the Christian in the first three chapters of Colossians, wives should behave in this way. The motivation is to look to your identity in Christ, look at who Christ is, look at what Christlikeness entails (in putting to death and putting on) and therefore do what is fitting for someone "in the Lord."
Command: Husbands, love you wives.
Motivation: And do not be harsh with them.
Technically, this is the only one of the seven commands that doesn't give a corresponding reason for the command. But I think the second half of the command (and do not be harsh with them) may be an implied motivation. Husbands should love their wives because no one wants to be dealt with harshly.
Command: Children, obey your parents in everything.
Motivation: For this pleases the Lord.
Considering everything else Paul has said about legalistic rules (2:18-23) we can be sure he is not arguing for kids to earn God's favor. But at the same time, it's clear that pleasing God ought to be one of the motivations we instill in our children. Kids should obey because Jesus likes it when they do.
Command: Fathers, do not provoke your children.
Motivation: Lest they become discouraged.
Here we see Paul reasoning based on the welfare of others. "Don't be a pain to your kids because you don't want them to be pained, do you?" Sometimes we insist on obedience based on the principle of treating others as we would like to be treated. This too is gospel logic.
Command: Slaves, obey in everything those who are your earthly masters, not by way of eye-service, as people-pleasers, but with sincerity of heart.
Motivation: Fearing the Lord.
Paul does not think it inappropriate to use fear as a motivation even among Christians. Obviously, this is not a servile fear before a vengeful God, but it is real fear nonetheless. The argument is: "Don't fake it. Don't put on a good show when people are watching and then turn into a cheat when no one is around. God is still watching and he knows what you are really like."
Command: Whatever you do, work heartily, as for the Lord and not for men.
Motivation: Knowing that from the Lord you will receive the inheritance as your reward.
Motivation: You are serving the Lord Christ.
Motivation: For the wrongdoer will be paid back for the wrong he has done, and there is no partiality.
The simple command is to work heartily. The reasons are many: (1) When you work you are actually working for Christ. (2) Christ will give you an inheritance when you work well. (3) The wrongdoer will be judged for doing wrong. Since Christ is your boss, giving bonuses and passing our demerits, work heartily.
Command: Masters, treat your slaves justly and fairly.
Motivation: Knowing that you also have a Master in heaven.
The reasoning here seems to be twofold. Masters should be just and fair because their Master in heaven is just and fair. They should also be good masters because they have a Master in heaven who will know if they aren't.
The point of this brief exegetical excursion is to show how multifaceted the Bible can be with its motivations for holiness. God can appeal to our identity, his pleasure, the good of others, his knowledge, his example, or his recompense. And this just in the span of nine verses. The gospel gets at our hearts and stirs up our wills in many different ways. It is a mistake to lock in on just one truth, whether that's adoption, justification, union with Christ, or whatever. As we preach and counsel and help others we should make liberal use of all the Bible's ways of making us holy.