The phrase "am source strength" can be expressed in a variety of different ways using synonyms. Instead of "am," you could use words like "amplify," "serve as," or "provide." Instead of "source," you could use "origin," "cause," or "root." And rather than "strength," you could use "force," "power," or "potency." By using different synonyms, you can add variety to your writing, making it more interesting and engaging to readers. Additionally, using synonyms can help you to express your ideas more clearly by allowing you to choose the perfect word to convey your intended meaning.