God is everlasting. He has always existed and always will exist. He has no beginning and he has no end. He is eternal.
According to Genesis 21:33 Abraham planted a grove in Beersheba, and called there on the name of the LORD, the everlasting God. If I could identify the location of that place in Beersheba today, I would not be surprised to see that the grove still survives even today because God is everlasting and the grove was dedicated to him as the everlasting God.
As Moses blessed the children of Israel before he died he declared that God is everlasting in Deuteronomy 33:27:
"The eternal God is thy refuge, and underneath are the everlasting arms: and he shall thrust out the enemy from before thee; and shall say, Destroy them.
A prayer of Moses is recorded in Psalm 90, verse 2 which states:
"Before the mountains were brought forth, or ever thou hadst formed the earth and the world, even from everlasting to everlasting, thou art God."
Isaiah asked the Israelites in Chapter 40, verse 28:
"Hast thou not known? hast thou not heard, that the everlasting God, the LORD, the Creator of the ends of the earth, fainteth not, neither is weary? there is no searching of his understanding."
And in Isaiah 57:15 God is declared to inhabit eternity:
"For thus saith the high and lofty One that inhabiteth eternity, whose name is Holy; I dwell in the high and holy place, with him also that is of a contrite and humble spirit, to revive the spirit of the humble, and to revive the heart of the contrite ones."
The prophet Jeremiah declares God an everlasting king in Jeremiah 10:10:
"But the LORD is the true God, he is the living God, and an everlasting king: at his wrath the earth shall tremble, and the nations shall not be able to abide his indignation."
The Apostle Paul tells us in Romans 1:20 that God has eternal power:
"For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse"
Paul closes the Book of Romans with the statement that God is eternal and had plans for all mankind even before he made the world that he kept secret.
"Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began,
But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith" Romans 16:25-26
It is fitting to close with a quote from I Timothy 1:17:
"Now unto the King eternal, immortal, invisible, the only wise God, be honour and glory for ever and ever. Amen."