Valmiki Ramayana Kishkindha Kanda Sarga 11 Shloka 90

तात O dear, तव your, तस्य च and his, यत् such, बले strength, स एव that alone, संशयः doubt, एकम् one, सालम् Sala tree, निर्भिद्य after splitling through, व्यक्तिः demonstrated, भवेत् will be known, बलाबले strength or otherwise.

'O Dear, therefore, I have my doubt about your relative strength. If you can split a sala tree with a single arrow then can your strength or weakness be demonstrated.