Colossians 3:23, 24 (NKJV)
There are a lot of things that motivate people: popularity, money, guilt, needs, and even fear. But what should our motivation be for the things that we do? Should we just do something because we can or because someone else wants us to do it? Should we do something because it will make us popular with other people or just because it will be beneficial for us? Colossians 3:23, 24 gives us the proper motivation for what we do; everything should be done for God because ultimately He is the One we serve and He will reward us for our work.
Sometimes people want us to do things, and they may even try to pressure us into doing something because there is a need or they might say if we don't do it something bad will happen, but again these are not reasons we should do things. Or if our motivation is simply one of personal gain we can be sure that there is not going to be much reward from God in that. Certainly God wants to bless us and give us good things but if we are selfish and only thinking about ourselves then we have the wrong motive. Paul wrote in 1 Corinthians 13 that if what he did was not done in love it meant nothing and he gained nothing.
God has a plan and a purpose for each and every person and we are at our best when we are following that plan and purpose. We can always start with the general will of God that we find in the Bible and from there we can go on to the specific will of God, this is where we get our motivation. God will show us what we need to do to fulfill His will and He can also show us what we should not get involved in. If we follow God's plan and allow Him to direct us then we will live a life that is focused on God and doing His will, this is the best motivation and it brings the best rewards!