20 This represents the Hebrew particle (כִּי, ki) that is normally rendered “for” or “because.” The particle here is meant to give the significance of the vision, not the rationale for the statement “you have observed correctly.”
21 Heb “watching over my word to do it.” There is a play on the Hebrew word for “almond tree” (שָׁקֵד, shaqed), which blossoms in January/February and is the harbinger of spring, and the Hebrew word for “watching” (שֹׁקֵד, shoqed), which refers to someone watching over someone or something in preparation for action. The play on words announces the certainty and imminence of the Lord carrying out the covenant curses of Lev 26 and Deut 28 threatened by the earlier prophets.

In other versions

Then the Lord said to me, “You have seen well, for I am watching over my word to perform it.”

The Lord said to me, “You have seen correctly, for I am watching to see that my word is fulfilled.”

The Lord said to me, “You have seen correctly, for I watch over my word to accomplish it.”

And the Lord said, “That’s right, and it means that I am watching, and I will certainly carry out all my plans.”

Then Yahweh said to me, “You did well to see, for I am watching over my word to perform it.”

Then said the Lord unto me, Thou hast well seen: for I will hasten my word to perform it.

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