The original German text begins with the following lines:
»Wann treffen wir drei wieder zusamm'?«
»Um die siebente Stund', am Brückendamm.«
»Am Mittelpfeiler.« »Ich lösche die Flamm'.«
Compare this with the opening lines of the translation by Dorothea Tieck, first published in 1832 (in: Shakspeare's dramatische Werke. Übersetzt von August Wilhelm Schlegel. Ergänzt und erläutert von Ludwig Tieck, Bd. 9. Berlin: Georg Andreas Reimer, 1832):
Wann kommen wir drei uns wieder entgegen,
Im Blitz und Donner, oder im Regen?
The first line asks, "When will the three of us meet [each other] again?" Fontane's "zusamm'" (a shortened form of "zusammen" that rhymes with "Brückendamm") is strictly speaking redundant but linguistically correct; see zusammentreffen in Wiktionary. Dorothea Tieck's Macbeth translation uses "entgegen" (see entgegenkommen in Wiktionary) instead of "zusammen" to achieve a rhyme with "Regen" (rain). [0]
For a translation that uses the same rhyme as Fontane's poem, see Wilhelm Jordan's translation, first published in 1865:
Wann kommen wir Dreie wieder zusammen
Bei Regen, Donner und Wetterflammen?
However, even for readers who weren't familiar with Wilhelm Jordan's translation, the reference to Macbeth should have been clear to German readers, especially since the lines that follow carry on the allusion, although less directly.[1]
The lines "“A bauble, a naught, / What the hand of man hath wrought!” correspond with the following German lines:
»Tand, Tand,
Ist das Gebilde von Menschenhand.«
Tand means "trifles, trinkets". The word appears to come from the phrase Nürnberger Tand (literally "trinkets from Nürnberg"), which referred to toys produced and sold in Nürnberg, where the "toy industry" took off in the fifteenth century. The translation as bauble does not appear to preserve this connection with toys.
Job 12:9 (in German: Hiob 12:9) reads as follows in Luther's Bible translation of 1545 [2]:
Wer weiß solches alles nicht, daß des HERRN Hand das gemacht hat,
Literally: "Who does not know that the LORD's hand made all this."
What remains from this line from Job/Hiob is "Hand". If the line in the poem was intended as an allusion to Job, Fontane's "Tand" contrasts strongly with God's creatures in the Bible book.
[0] For comparison, here are a few other German translations that existed during Fontane's lifetime.
Wenn kommen wir drey uns wieder entgegen,
In Donner, Blizen oder Regen?
Na! sagt, wo man sich wiederfind't
In Donner, Bitz o'r Schlackerwind?
Wann kommen wir drei uns wieder entgegen,
In Donner, in Blitzen oder in Regen?
[1] Several online versions of the poem even cite "When shall we three meet again (Shakespeare: Macbeth)" as a kind of motto, e.g. on www.martinschlu.de, Levrai.de and Phantasus.de but not on Deutschland-Lese. If that quote was part of the version that Fontane published, the reference would have been blatantly obvious.
[2] For comparison I also cite a modern version of the same line in the "Luther 2017" translation:
Wer erkennte nicht an dem allen, dass des HERRN Hand das gemacht hat,
Literally: "Who does not recognise in all of this [the animals and plants in the preceding lines] that the hand of the LORD made them".