In my statement of purpose, I am using certain arguments by scholars of my field (IR). Will it be advisable to use referencing, or might it be to my disadvantage as an unnecessary attempt to boast on my knowledge in that field.
If you're going to use others' ideas or arguments, use citations.
If you use someone else's ideas in any piece of academic writing, always include citations with sufficient detail for your readers to locate the source of the ideas. To do otherwise would be plagiarism.
Correct attribution of ideas is not boastful; it's a basic requirement of writing.
Will it be advisable to use referencing, or might it be to my disadvantage as an unnecessary attempt to boast on my knowledge in that field.
I can hardly imagine an admission committee that would hold it against you that you already have knowledge of the field you would want to get into. You should be fine.
Also - it is an application, a certain amount of (rightful) boasting is certainly required. An SOP is not the right place for understatement.