Russian Easter Wordlist [downloadable]
Со све́тлым пра́здником Па́схи!
Happy Easter to everybody who celebrates this holiday!
По-русски: Со све́тлым пра́здником Па́схи!
Let’s look into the phrase structure: preposition Со (we add О to C as the following word begins with С too)+ све́тлый пра́здник Па́схи in Instrumental case (literally with a bright holiday of Easter).
Another, more religious way to congratulate on this Day is to say: Христо́с воскре́с! Christ is risen! And the answer should be Вои́стину воскре́с! Indeed, He is risen!