There is both free will and predestination. The two are not contradictory.
Many people use the concept of predestination to say that no matter what we do, it is useless, because God will choose who to take to heaven.
But that might just be making an excuse to justify unbelief.
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We believe God knows all things and He knows them beforehand. So He knows who will love Him and who will hate Him.
It is those who hate Him who will be punished, as it is written:
"Your hand will find all Your enemies;
Your right hand will find those who hate You.
You shall make them as a fiery oven in the time of Your anger;
The Lord shall swallow them up in His wrath,
And the fire shall devour them." (Psalm 21: 8-9)
Those who believe in God and do His will are those who love Him.
For those who love God (whom He knew beforehand), He has predestined us to be conformed to His image:
"And we know that God causes all things to work together for good to those who love God, to those who are called according to His purpose. For those whom He foreknew, He also predestined to become conformed to the image of His Son, so that He would be the firstborn among many brethren; and these whom He predestined, He also called; and these whom He called, He also justified; and these whom He justified, He also glorified." (Romans 8:28-30)
We also know whether we have been predestined or not. If we believe in Jesus and seek to obey Him, then we know we are predestined.
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God gives us free will and we are responsible for what we choose.
If we choose God and obey Him, then we show that we are the ones who love Him and who are predestined.
The verses in Romans 8:28-30 show that God predestines those who would love Him. Who are those who love Him? They are those who CHOOSE to love Him by believing in the Son and obeying Him.
Jesus said, "He who has My commandments and keeps them is the one who loves Me; and he who loves Me will be loved by My Father, and I will love him and will disclose Myself to him" (John 14:21).
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From our perspective, if we CHOOSE to love God, then we are the ones who are PREDESTINED.
From God's perspective, because He is God, He KNOWS BEFOREHAND those who would CHOOSE to love Him.
Besides this, we can trust that God makes the right choices always.