At the Last Supper, Jesus said to his disciples:
“Peace I leave with you; my peace I give you; a peace the world cannot give, this is my gift to you. Do not let your hearts be troubled and do not be afraid.” (John 14.27)
“I have said these things to you so that my joy may be in you, and that your joy may be complete.” (John 15:11)

“Let nothing disturb you, Let nothing frighten you, All things are passing. God alone is unchanging. Patience brings all things. Whoever has God, lacks nothing; God alone suffices.”
St Teresa of Avila