Men tend to fret over the motives behind others’ actions. Instead, men should trust the Lord to deal with the motives at the judgment seat of Christ.
It is always right to do right, but it is more perfectly right to do right for the right reasons. In other words, serve the Lord, but do so out of a pure motive.
How would making your motive match the Lord's motive change how you approach the Christian life (from witnessing to praying to Bible reading and so on)?