1 Corinthians 3:11-15:
11) For other foundation can no man lay than that is laid, which is Jesus Christ.
12) Now if any man build upon this foundation gold, silver, precious stones, wood, hay, stubble;
13) Every man's work shall be made manifest: for the day shall declare it, because it shall be revealed by fire; and the fire shall try every man's work of what sort it is.
14) If any man's work abide which he hath built thereupon, he shall receive a reward.
15) If any man's work shall be burned, he shall suffer loss: but he himself shall be saved; yet so as by fire.
Hello,
As Christians, our faith is laid upon the foundation of Christ. Every single thing we do after we have been born again is building on that foundation. It is possible for us to do things that will pass God's approval test or things that will not pass the test.
Now the only way we can do things that please him is as we let Jesus live and work through us. In John 15, we are told that without Jesus we can do nothing. But as we abide in Christ, who in that chapter is spoken of as the Vine, then we as branches bring forth much fruit. In other words, the things we say and do will be useful and pleasing to God.
If we do not abide in Christ and let him live through us, things we do will be unacceptable to God, even if they are "good" things, because if we do not do them for the right reasons and with the right spirit, they are worthless to the cause of our Lord.
We will give account to God someday for all that we have done as Christians. This should cause us to be fearful and diligent to do the things we should. Though these verses do not specify what the "rewards" will be for those who serve Him nor the "losses" for those who do not, just the words themselves should be enough. If the Creator of heaven and earth rewards someone, they will be rewarded indeed. If he causes them to suffer loss, that is something to be feared and avoided.
The comforting aspect of all this is that even the Christian who builds some wood, hay and stubble upon the foundation will still be saved. I am glad that the good Shepherd takes care of His sheep and "they shall never perish, neither shall any man pluck them out of [his] hand." (John 10:28)
I hope this was helpful.