Psalm 97:1-2,7-12

 1 The LORD is King;
let the earth rejoice;
let the multitude of the isles be glad.

2
Clouds and darkness are round about him,
righteousness and justice are the foundations of his throne.

Confounded be all who worship carved images
and delight in false gods!
Bow down before him, all you gods.

         Zion hears and is glad, and the cities of Judah rejoice,
         because of your judgments, O LORD.

         For you are the LORD, most high over all the earth;
         you are exalted far above all gods.

         The LORD loves those who hate evil;
         he preserves the lives of his saints
         and delivers them from the hand of the wicked.

       Light has sprung up for the righteous,
         and joyful gladness for those who are truehearted.

Rejoice in the LORD, you righteous,
and give thanks to his holy Name.

From the Great Cloud of Witnesses:

The son of a weathy Englishman, Patrick was kidnapped and taken to Ireland in slavery in the beginning of the fourth century. After six years, he escaped and returned to his native England. While there, he had a conversion experience and heard God telling him to return as a missionary to Ireland. After fifteen years of study and preparation, he returned to the land of his captivity, a captivity that had prepared him to speak the language and to be familiar with the customs of the Irish people. Although there were some Christians in Ireland, the majority of the people were pagan and the influence of the Druid priests was strong. Patrick challenged their knowledge and authority and won thousands to Christianity. The prayerful Breastplate of St Patrick speaks both to his experience among the Druids and his deep faith in God. It includes the famous stanza:  "Christ be with me, Christ within me,Christ behind me, Christ before me, Christ beside me, Christ to win me, Christ to comfort and restore me. Christ beneath me, Christ above me, Christ in quiet, Christ in danger, Christ in hearts of all that love me, Christ in mouth of friend and stranger."(see link below for full prayer) 

History channel has videos and further info:  http://www.history.com/topics/who-was-saint-patrick

Breastplate of St Patrick: http://www.prayerfoundation.org/st_patricks_breastplate_prayer.htm

Collect:

Almighty God, in your providence you chose your servant Patrick to be the apostle of the Irish people, to bring those who were wandering in darkness and error to the true light and knowledge of you: Grant us so to walk in that light that we may come at last to the light of everlasting life; through Jesus Christ our Lord, who lives and reigns with you and the Holy Spirit, one God, for ever and ever. Amen.