Here are 3 examples of synonomous parallelism in the Bible...
1. Psalm 118: 2-4~ " Let Israel say: 'His love endures forever.' Let the House of Aaron say: 'His love endures forever. Let those who fear the Lord say:'His love endures forever.' "

2. Isaiah 34:1~ "Come near, you nations, and listen; pay attention you peoples! Let the earth hear, and all that is in it, the world, and all that comes out of it.

3. Exodus 34: 6~ "And he passed in front of Moses, proclaiming, ' The Lord, the Lord, the compassionate and gracious God, slow to anger, abounding in love and faithfulness, maintaining love to thousands, and forgiving wickedness, rebellion and sin. Yet He does not leave the guilty unpunnished; he punishes the children and their children for the sin of the fathers to the third and fourth generation.

--> This last passage is full of repetition with in itself, I think for the purpose of highlighting its importance. What is cooler is that this phrase is repeated throughout the Bible. It is obviously pretty important to the message of the Gospel...even here in the Hebrew scriptures.
ex. Psalm 103 (my favorite!), Numbers 14: 18, Nehemiah 9: 16-19, etc. It is all over!