Matthew 6:9b

Πάτερ ἡμῶν ὁ ἐν τοῖς οὐρανοῖς·ἁγιασθήτω τὸ ὄνομά σου·

Our father in heaven hallowed be you name


 * The first line of the Lord's Prayer.
 * Πάτερ ἡμῶν - Πάτερ is in the vocative case. "O father". From lexical form πατήρ.
 * ἐν τοῖς οὐρανοῖς - in the heavens. Notice the plural form. Dative case. ἐν takes dative.
 * ὁ ἐν τοῖς οὐρανοῖς - this phrase functions as an adjective. Hence the ὁ. It father was not in the vocative form, the phrase could have been ὁ πατήρ ἡμῶν ὁ ἐν τοῖς οὐρανοῖς, showing clearly the common article noun article adjective construction. But the vocative case doesn't use the article while the rest of the construction remains the same.
 * ἁγιασθήτω - aorist passive imperative 3P sg form of the verb ἁγιάζω (I set apart as holy, I sanctify, the KJV translation I hallow is convenient as a single word). So ἁγιασθήτω means "may ... be hallowed", or "hallowed be .... ". In modern speech, "may your name be regarded as holy".
 * τὸ ὄνομά σου - the name yours or your name. An example of the enclitic effect of σου. It doesn't have an accent but pushes its accent onto the previous word, or rather it attaches to the previous word for the purpose of applying accenting rules. Since accents can only be placed on the last three syllables of a word-group, the original accent of ὄνομα is too early. So another accent is added, ὄνομά.