Al-Mujadilah - 58:4

فَمَن لَّمْ يَجِدْ فَصِيَامُ شَهْرَيْنِ مُتَتَابِعَيْنِ مِن قَبْلِ أَن يَتَمَاسَّا فَمَن لَّمْ يَسْتَطِعْ فَإِطْعَامُ سِتِّينَ مِسْكِينًا ذَلِكَ لِتُؤْمِنُوا بِاللَّهِ وَرَسُولِهِ وَتِلْكَ حُدُودُ اللَّهِ وَلِلْكَافِرِينَ عَذَابٌ أَلِيمٌ
[58:4]
But whoever has not the means, let him fast for two months successively before they touch each other; then as for him who is not able, let him feed sixty needy ones; that is in order that you may have faith in Allah and His Messenger, and these are Allah's limits, and the unbelievers shall have a painful punishment.
And if any has not (the wherewithal), he should fast for two months consecutively before they touch each other. But if any is unable to do so, he should feed sixty indigent ones, this, that ye may show your faith in Allah and His Messenger. Those are limits (set by) Allah. For those who reject (Him), there is a grievous Penalty.
And he who findeth not (the wherewithal), let him fast for two successive months before they touch one another; and for him who is unable to do so (the penance is) the feeding of sixty needy ones. This, that ye may put trust in Allah and His messenger. Such are the limits (imposed by Allah); and for disbelievers is a painful doom.