'Let us make man'
A plural of majesty, an address to a divine council, or an early Trinitarian reading of 'let us make man in our image'.
Genesis 1:26-27
26God said, “Let’s make man in our image, after our likeness. Let them have dominion over the fish of the sea, and over the birds of the sky, and over the livestock, and over all the earth, and over every creeping thing that creeps on the earth.”
27God created man in his own image. In God’s image he created him; male and female he created them.
What each tradition says
Rabbinic / Midrashic
Rabbi Shmuel bar Naḥman said in the name of Rabbi Yonatan that when Moses was writing the Torah, he reached the verse “And God said: Let us make Man in our image, in our likeness.” Moses asked God: “Master of the universe, why do you provide the heretics with basis for a claim?”
Bereshit Rabbah, a saying of Rabbi Shmuel bar Naḥman in the name of Rabbi Yonatan; English: The Sefaria Midrash Rabbah, 2022, Bereshit Rabbah (Genesis Rabbah) — Comment on Genesis 1:26 (Bereshit Rabbah 8:8)
Patristic
Hilary of Poitiers argues that the words "Let Us make" and "Our" are inconsistent with solitude. Since an isolated being cannot be partner to himself, such wording cannot be used except to a companion.
Catholic
Aquinas argues that if man were made only to the Son's image, the Father would have said "to Thy image," not "Let Us make man to Our own image and likeness." So the sense is not that the Father made man to the Son's image only, but that the Divine Trinity made man to Its image, the whole Trinity.
Thomas Aquinas (1225-1274); trans. Fathers of the English Dominican Province (1920), Summa Theologiae, Prima Pars (New Advent edition) — Ia, q. 93, a. 5, Reply to Objection 4 (on 'Let Us make man to Our own image and likeness')
Orthodox
Basil reads "Let us make man," not "Let man be made," as showing there is not only one Person. He says the preaching of theology remained enveloped in shadow before the appearance of the one to be instructed, but now the creation of man is expected, so faith unveils herself and the dogma of truth appears in all its light.
Basil the Great (c. 330-379), The Hexaemeron (trans. Blomfield Jackson), in Nicene and Post-Nicene Fathers, ser. 2, vol. 8 (New York: Christian Literature Publishing Co., 1895) — Homily IX ('The creation of terrestrial animals'), §6, on Genesis 1:26
Reformed / Protestant
Calvin states that Christians properly contend from this testimony that there exists a plurality of Persons in the Godhead. God summons no foreign counsellor; hence we infer that he finds within himself something distinct, as his eternal wisdom and power reside within him.
John Calvin (1509-1564), Commentaries on the First Book of Moses Called Genesis, vol. 1 (trans. John King; Edinburgh: Calvin Translation Society, 1847) — Commentary on Genesis 1:26
Evangelical
John Wesley reads “Let us make man” as the three persons of the Trinity—Father, Son, and Holy Ghost—consulting and concurring in it. He says man, when made, was to be dedicated and devoted to Father, Son, and Holy Ghost.
John Wesley (1703-1791), Explanatory Notes upon the Old Testament (1765; CCEL's 'Wesley's Notes on the Bible') — Note on Genesis 1:26