God is a forgiving God, then is there really need for us to be judged on the judgement day?"
You asked: "If God is a forgiving God, then is there really need for us to be judged on the judgement day?"
God is a forgiving and caring God. When you ask forgiveness for your past, He forgives and cleans us. Others around us may not be so forgiving, but Jesus gives us a new start, when we come to him and ask forgiveness.
He has taught us that there will be two 'Judgments'.
First for the one who is a follower of Jesus, not just a 'Church Member', but for the one who loves the Lord, we will appear before him to be judged on how well we did what he asked us. The Judgment is not about salvation, but about rewards. Here is what the apostle Paul wrote to the Christians in Corinth.
1Corinthians 3:13-15 "the workmanship of each person will become evident, for the day of judgment will show what it is, because it will be revealed with fire, and the fire will test the quality of each person's action. If what a person has built on the foundation survives, he will receive a reward. If his work is burned up, he will suffer loss. However, he himself will be saved, but it will be like going through fire."
2Corinthians 5:17 Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
Revelation 20:6 Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years.
Now there is a second Judgement of the people who refused to serve Jesus.
Revelation 20:7 And when the thousand years are expired . . .
Rev 20:11 And I saw a great white throne, and him that sat on it, from whose face the earth and the heaven fled away; and there was found no place for them.
Rev 20:12 And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
Rev 20:13 And the sea gave up the dead which were in it; and death and hell delivered up the dead which were in them: and they were judged every man according to their works.
Rev 20:14 And death and hell were cast into the lake of fire. This is the second death.
Rev 20:15 And whosoever was not found written in the book of life was cast into the lake of fire.
So, if you follow Jesus, you need not fear the second judgment, but only look forward to the first Judgment, when Jesus will reward you for what you did for him.
Here is what Jesus himself said: Matthew 10:42 "And whosoever shall give to drink unto one of these little ones a cup of cold water only in the name of a disciple, verily I say unto you, he shall in no wise lose his reward."