Physics, in this case is in harmony with what is set forth in Genesis, that almighty God created a tri-universe of space, time and matter. The specific reasons for the creation of time are not stated directly. A number of explanations would be satisfactory.
Firstly, time could have been created to demonstrate the finitude of man and creation, both being subject to time and within time, in contrast to the almighty creator, who is both outside of time and eternally unlimited by time.
Secondly, as suggested by the first answer above, time is part of the physical reality of the universe, in which are also space and matter, all three of which interact with each other.
Additionally:
From the biblical perspective, it's revealed that God is working on a "plan," that is on a "time schedule."
"He must remain in heaven UNTIL THE TIME COMES for God to restore everything, as He promised long ago through His holy prophets." (Acts 3:21 NIV)
"And you are the heirs of the prophets and of the covenant God made with your fathers... 'Through your offspring all peoples on earth WILL BE blessed.'" (verse 25)
"What I am saying is that as long as the heir is a child, he is no different from a slave, although he owns the whole estate. He is subject to guardians and trustees UNTIL THE TIME set by his father. So also, when we were children, we were in slavery under the basic principles of the world. But when THE TIME HAD FULLY COME, God sent His Son..." (Gal.4:1-4 NIV).
"...whenever you eat this bread and drink this cup, you proclaim the Lord's death UNTIL HE COMES." (I Cor.11:26 NIV)
"THEN the end will come, when He [Jesus] hands over the Kingdom to God the Father AFTER He has destroyed all dominion, authority and power. For He must reign UNTIL He has put all His enemies under His feet." (I Cor.15:24-25 NIV)
Our Creator has "allotted man this time" for a number of reasons... one of which is for the purpose of working out the lawful and just "restoration of all things" that Satan and his angels disrupted in the beginning -- including the redemption of mankind, who is presently AT THIS TIME bound in slavery to the "basic principles" of this world [Satan's world].
Another reason for "creating time"... is that the "building of character" [whether it's good character or bad]... takes time. God is seeking to build Righteous character in His "heirs" [His Children]. And that requires that they must learn evil during that journey in order that they can make an informed decision as to whether or not they will choose to reject the evil [overcome it through Jesus Christ] -- or succumb to it.
"...we are God's Children. Now if we are Children, then we are heirs -- heirs of God and co-heirs with Christ, if indeed we share in His sufferings in order that we may also share in His Glory." (Rom.8:16-17 NIV)
Children require the TIME to grow and develop. Fathers seek to teach their children the right way to live and conduct themselves, that they might develop Righteous character -- and be happy. For Righteous character is not acquired by fiat. It's fought for.
"...you also were included in Christ when you heard the Word of Truth, the gospel of your salvation. Having believed, you were marked in Him with a seal, the promised Holy Spirit, who is a deposit guaranteeing our inheritance UNTIL THE REDEMPTION of those who are God's possession -- to the praise of His Glory." (Eph.1:13-14 NIV)
"...this is my prayer: that your love may abound more and more in knowledge and depth of insight [character development] so that you may be able to discern what is best amd may be pure and blameless UNTIL THE DAY OF CHRIST [the prophesied Day of the Lord; the future time of Jesus Christ's return to earth], filled with the fruit of Righteousness that comes through Jesus Christ -- to the Glory and Praise of God." (Philipp.1:9-11 NIV)
"Fight the good fight of the faith... I charge you to keep this commandment without spot or blame UNTIL THE APPEARING of our Lord Jesus Christ, which God will bring about IN HIS OWN TIME..." (I Tim.6:12-15 NIV).
So, time is a commodity [like everything else in this polluted, throw-away satanic world], that God's Children must re-learn and re-think and be reeducated not to waste and take for granted. As the song goes: 'you don't know what you've got till it's gone. Pave Paradise... put in a parking lot."
Time is critical... and it's passing away. This unbelieving high-tech world wastes it... wallowing in unrestraint, over-indulgence and degradation; excessive drink and promiscuous sex. It's preoccupied with frivolity... the cares of the world... and carelessness.
Time is also for the learning of "patience."
"Be patient, then, brothers, UNTIL the Lord's coming. See how the farmer waits for the land to yield its valuable crop and how patient he is for the autumn and spring rains. You too, be patient and stand firm, because the Lord's coming is near." (James 5:7-8 NIV)
These are some of the reasons why the Bible says time was created.