One can't help but sigh that time passes so quickly.
Tips
grammar
The 禁 here is read jīn (first tone), NOT jìn. When 禁 means 'to endure/bear,' it's jīn. When it means 'to prohibit/ban,' it's jìn. 不禁 (bù jīn) = can't refrain; 禁止 (jìnzhǐ) = to prohibit.
usage
不禁 is more literary than 忍不住 (rěn bu zhù), which also means 'can't help but.' Use 不禁 in writing and formal speech, 忍不住 in casual conversation.