وعليكم السلام ورحمة الله وبركاته Imam Ash Shawkani رحمه الله said: No proof from the Prophet صلى الله عليه وسلم has come in this and there is no proof in that which has been narrated from some of the Companions رضي الله عنهم . And that which Allah عز وجل necessitated from the one who did not fast (the entirety of) Ramadan or some of it is that he (just) makes up for it as He سبحانه said " فَعِدَّةٌ مِنْ أَيَّامٍ أُخَرَ the same number (should be made up) from other days ". And the one who makes up (the missed fasts of) Ramadan after the passing of a year or two or more than that then he has indeed done what Allah عز وجل has made obligatory upon him which is 'the same number from other days'. And Allah عز وجل did not restrict these (other) days that they they should be from the same year in which the fasts were missed, neither did He سبحانه made Kaffara obligatory upon the one who delays it (until the upcoming years). (End quote) [ As Sail Al Jarrar, page 289 ]. And there is no doubt that it is better to hasten towards all of the good deeds and from them is making up the missed fasts of Ramadan since a person does not know when his time (of death) will come to him and Allah عز وجل has said : " وَسَارِعُوٓا۟ إِلَىٰ مَغْفِرَةٍۢ مِّن رَّبِّكُمْ And march forth in the way (which leads to) forgiveness from your Lord " [3:133] and He جل علا said whilst describing the believers " أُو۟لَـٰٓئِكَ يُسَـٰرِعُونَ فِى ٱلْخَيْرَٰتِ It is these who hasten in the good deeds " [23:61]. So the best of good deeds is that which is done quickly. As for the Hadith of Aisha رضي الله عنها related to Qadha then it is from that which shows it is befitting to make up missed fasts quickly before the next Ramadan enters. But as for it being an obligation and a condition (for the validity of the Qadha) then there is something (some weakness) regarding that as preceded from Imam ash Shawkani may Allah عز وجل have mercy on him. And Allah عز وجل knows best.