I, the LORD, am its keeper: Unlike 5.1, it is clear that Yahweh is the speaker here. Its keeper means that he tends and protects the vineyard. As in the previous verse, the pronouns referring to the vineyard (its and it) are feminine singular in Hebrew (see the comments there). For this line New Jerusalem Bible has “I, Yahweh, am its guardian.”

Every moment I water it describes in part what its keeper means. He waters it to ensure that it grows well. Every moment renders the same Hebrew expression translated “for a little while” 26.20. Here it means “all the time,” as in Job 7.18 and Ezek 26.16. Good News Translation expresses it well with “continually.”

Lest any one harm it, I guard it night and day: The connector Lest introduces what Yahweh tries to avoid. He does not want anyone to harm the vineyard. The Hebrew verb rendered harm is the same one translated “punish” in verse 1 and 26.21. The Hebrew verb for guard comes from the same root as the word for keeper. Night and day means “constantly.” Yahweh always watches over the vineyard, so that no one damages it. Some languages may prefer to say “day and night” for naturalness (so Contemporary English Version, Bible en français courant, Die Bibel im heutigen Deutsch).

For the translation of this verse consider the following examples:

• I, Yahweh, am the guardian of the vineyard;
I water it constantly,
I guard it night and day to prevent any harm to it.

• I, Yahweh, guard it, watering it constantly;
I guard it day and night in case people want to damage it.

Quoted with permission from Ogden, Graham S. and Sterk, Jan. A Handbook on Isaiah. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here .