The Psalmist wrote it is a good thing to do four things because the Lord had made him glad through his work and had caused him to triumph in the works of his hands.  Are you ever glad? Do you ever triumph?  You should be glad all the time and triumph all the time because of the Lord.  When you are glad and you triumph…

It is a good thing:

To give thanks unto the Lord.  And this is not silently.  We ought to give thanks unto the Lord every time the Lord makes us glad and every time we triumph so others will know that the Lord did this.

To sing praises unto thy name.  We should be able to lift up our voice and sing the praises of the Lord.  Paul and Silas did while they were in prison and the warden and his family were saved.

To shew forth thy lovingkindness in the morning.  Lovingkindness is tender and benevolent affection.  He said “shew forth”.  Others should know that we are loved by the Lord.  In this way they will know that they can be loved, too.  God’s love supersedes any other love known to men.

To shew forth thy faithfulness in the evening.  Faithful is firm in adherence to promises.  He said “shew forth”.  Others should know when the Lord has fulfilled a promise in our lives.  He always keeps his words.

Conclusion: You are going to be in place where your voice will affect others.  Jesus sang a hymn before his crucifixion.  Don’t be ashamed to let others know that you thank the Lord and praise him, and that he loves you and is faithful to his words.