To Be Seen or Not Seen, That is the Question!

In Jesus' Sermon on the Mount, He says both, "Let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven," AND, "When you give to the needy, do not let your left hand know what your right hand is doing, so that your giving may be in secret. And your Father who sees in secret will reward you." So which is it? Are we to give and do good works to be seen or are we to do them in secret?