In Psalm 119:124 it says "deal with your servant according to your 'love'" but in previous verse it talks about "preserve my life according to your  word" vs 37 "do good according to your  word" vs 65. Also in verse 107. Why is it that he says  “love”  in that verse instead of  “word”  like in the previous verse?

We know God always keeps His word. 2 Cor. 1:20 (NIV), "For no matter how many promises God has made, they are 'Yes'  in Christ. And so through him the 'Amen' is spoken by us to the glory of God." What a wonderful assurance. I love that old saying,

God said it, I believe it, That's good enough for me!

Additionally, it's important to remember God's character is love. ( 1 John 4:8) Whatever God does, He does out of love. He never violates this principle. Therefore, all God's words are based on love. Psalm 119:124 is simply an affirmation that God will always help us from the basis of love as expressed in His word throughout the Bible.