מגדיל [מִגְדּ֖וֹל] יְשׁוּע֣וֹת מַלְכּ֑וֹ וְעֹֽשֶׂה־חֶ֧סֶד לִמְשִׁיח֛וֹ לְדָוִ֥ד וּלְזַרְע֖וֹ עַד־עוֹלָֽם׃ (פ)
A tower of salvation is He to His king; And showeth mercy to His anointed, To David and to his seed, for evermore.
Read midrashic interpretation of II Samuel 22:51: and classical rabbinic exegesis.