What is the Biblical basis that God "cannot" act against his nature?

Omnipotence is often loosely defined as, "having the ability to do anything." As some would argue God could not create a square circle, or simultaneously exist and not exist, He must not be--by definition--omnipotent.

This conclusion rests on the assumption that omnipotence stands or falls on the limits of someone's imagination; however, the ability to answer an assemblage of contradictory ideas does not determine whether God is all-powerful.

The true determination for omnipotence is, can God do whatever He intends to do, whenever and in whatever way He intends to do it?

1. The Bible declares He can.

   • Psalm 115:3 [MEV]: "But our God is in the heavens; He does whatever He pleases."
   • Daniel 4:35 [MEV]: "...He does according to His will in the army of heaven and among the inhabitants of the earth. And no one can stay His hand or say to Him, 'What have You done?'"
   • Isaiah 43:13 [MEV]: "Indeed, from eternity I am He; there is no one who can deliver out of My hand; I act, and who can reverse it?"
   • Luke 1:37 [MEV]: "For with God nothing will be impossible.”
   • Luke 18:27 [MEV]: "He said, “What is impossible with men is possible with God.”

2. With regard to your question:

   • Hebrews 6:18 [MEV]: "So that by two immutable things, in which it was impossible for God to lie, we who have fled for refuge might have strong encouragement to hold fast to the hope set before us."

   • "Impossible," as used here, has two possible meanings; either God lacks the power to lie; or God is unable to lie [Strong's G102].

   • As can be seen above, God can do whatever He chooses to do; whenever and however He chooses to do it. Therefore, the meaning of "impossible" in Hebrews 6:18 is that God cannot lie.

   • This interpretation is confirmed in Titus 1:2 [MEV]: "in hope of eternal life which God, who cannot lie, promised before the world began"

God cannot lie because it is not in His nature. As He is the God of truth [Psalm 31:5], it is impossible for Him to lie.

It is therefore true that He will not act against His nature; it is also true that He cannot act His nature.

God can do whatever he wills or wants to do . Anything and everything one could think of ! However, because everything possible is not included in his nature ( God telling a lie, to not be all loving , or limit himself to what he can see or do ...etc) , which means he would change in nature and subsequently we would change as well. Everything on earth and the universe comes from the nature of God. And the nature of God is eternal, he can go against his nature if he wanted to, but we trust and come to believe that he won’t. If God changed his nature , in the blink of an eye, we would cease to exist. ( or at the very least be changed forever )

I believe that your question, although well intentioned, is irrelevant and unanswerable. II Peter 3:8 eludes to the truth of the matter:

But do not overlook this one fact, beloved, that with the Lord one day is as a thousand years, and a thousand years as one day.

God is outside of time. From our perspective he was, is, and will be, all at the same time, just as Boethius speculated. So the question "Does God's omnipotence give him the power to do something sinful or against his nature?" is irrelevant because it presupposes choice. Choice presupposes being in time. God has done, is doing, and will do, according to his nature which is completely good.

The Concise Oxford English Dictionary (11th ed.) defines "nature" as "the basic or inherent features, qualities, or character of a person or thing."

For God to act against His nature would mean, employing the COED definition of "nature", that He would be exhibiting features, quality, or character that were not basic or inherent to Him. In essence, He would change.

Scripture teaches that God does not change. According to James, there is no variableness nor shadow of turning in God (James 1:17). The Lord said to Malachi (3:6), For I am the Lord, I change not.