The Catechism in Questions & Answers

551. Who promised the return of Jesus Christ?

Jesus Christ Himself promised His Apostles: “And if I go and prepare a place for you, I will come again and receive you to Myself; that where I am, there you may be also” (John 14: 3).
This promise of Jesus was reinforced by angels at His ascension into heaven: “This same Jesus, who was taken up from you into heaven, will so come in like manner as you saw Him go into heaven” (Acts 1: 11).