Explain God’s singular vs plural nature

The references in Genesis 1 to God’s plural nature and to His singular nature are examples of the mystery of the Trinity. Scripture consistently represents God as both One God and also as Three Persons:

God is One:

Deut. 6:4  “Hear, O Israel! The Lord is our God, the Lord is one!

Mark 12:28  One of the scribes came and heard them arguing, and recognizing that He had answered them well, asked Him, “What commandment is the foremost of all?”
Mark 12:29 Jesus answered, “The foremost is, ‘Hear, O Israel! The Lord our God is one Lord;
Mark 12:30 and you shall love the Lord your God with all your heart, and with all your soul, and with all your mind, and with all your strength.’

Mal. 2:10  “Do we not all have one father? Has not one God created us? Why do we deal treacherously each against his brother so as to profane the covenant of our fathers?

James 2:19 You believe that God is one. You do well; the demons also believe, and shudder.

God is Three Persons:

Ex. 35:30  Then Moses said to the sons of Israel, “See, the Lord has called by name Bezalel the son of Uri, the son of Hur, of the tribe of Judah.
Ex. 35:31 “And He has filled him with the Spirit of God, in wisdom, in understanding and in knowledge and in all craftsmanship;

Num. 11:25 Then the Lord came down in the cloud and spoke to him; and He took of the Spirit who was upon him and placed Him upon the seventy elders. And when the Spirit rested upon them, they prophesied. But they did not do it again.

Matt. 12:32 “Whoever speaks a word against the Son of Man, it shall be forgiven him; but whoever speaks against the Holy Spirit, it shall not be forgiven him, either in this age or in the age to come.

John 15:26  “When the Helper comes, whom I will send to you from the Father, that is the Spirit of truth who proceeds from the Father, He will testify about Me,

As we see in these various examples, God is described in scripture both as Father, Son and Holy Spirit, and yet scripture also describes God as “One.” Therefore, we must acknowledge both the Three Persons of God and at the same time that God is One. This seemingly contradictory truth is also evident in the Creation account where we see God describing Himself both in plural and singular terms. 
 

Scripture quotations taken from the (NASB®) New American Standard Bible®, Copyright © 1995, 2020 by The Lockman Foundation. Used by permission. All rights reserved. www.lockman.org