King James Bible (Genesis 1:26)
And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.
John Dummelow’s Commentary on the Bible
26. Let us make man] the crowning work of creation and its highest development. The plural form ‘us,’ which occurs again Genesis 3:22; Genesis 11:7 and Isaiah 6:8, has been interpreted of the Holy Trinity, but this would be anticipating a doctrine which was only revealed in later ages. The thought is perhaps that of God speaking in a council of angelic beings, or the form of the word may indicate a plural of majesty: see on ‘God’ Genesis 1:1.
Expository Notes of Dr. Thomas Constable
We should not use it as a formal proof of the Trinity since this reference by itself does not prove that one God exists in three persons. [Note: See Ross, Creation and . . ., p112; Wenham, pp27-27; Oswald Allis, God Spake by Moses, p13.]
Ellicott’s Commentary for English Readers
It is not a formal proof of the Trinity, nor do believers in the inspiration of Holy Scripture so use it.
Keil & Delitzsch Commentary on the Old Testament
..modern commentators, on the contrary, regard it either as pluralis majestatis; or as an address by God to Himself, the subject and object being identical; or as communicative, an address to the spirits or angels who stand around the Deity and constitute His council.