The antonyms for the phrase "fall on one's knees" include stand tall, keep upright, stay on one's feet, maintain a steady balance, and remain stable. These antonyms suggest a sense of strength, resilience, and stability, rather than surrender or submission. Some possible synonyms for the phrase "fall on one's knees" include kneeling, bowing, prostrating, groveling, or begging. These synonyms suggest a sense of humility, supplication, or deference, rather than strength or autonomy. Depending on the context, using antonyms or synonyms of "fall on one's knees" can convey very different meanings and tones.