Indeed, a people strive hard in Ramadaan and when it finishes they abandon the actions.

Sheikh Saaleh Al-Fawzaan was asked: 'Some of the people, with great regret, you see them in Ramadaan devoting themselves to the five (daily) prayers, to the taraaweeh (prayers) and the night prayer and the recitation of the noble Qur'aan...and when Ramadaan finishes, they abandon that or most of it! So, what is the ruling about them? And are those righteous actions of theirs in Ramadaan accepted?  And what is your advice to the likes of these?' So, the Sheikh replied by saying: 'As for striving hard in Ramadaan with righteous actions, then this is something good, and Ramadaan has a specialness to it and it is a great time of the year. However, it is required from the Muslim that he strive hard in doing the good actions throughout all his lifespan and all his life and in all the months, because his life is a valuable opportunity and he is heading towards an abode which needs action, for indeed, the recompense in the abode of the hereafter is but indeed upon action.   So, it is required from the Muslim that he takes advantage of his life in the world by doing righteous actions, and that he singles out the days of virtue and the times of the year which are of goodness, like the month of Ramadaan, with extra hard striving.   As for these people who neglect and squander away the obligatory duties and the prayers, then when Ramadaan comes they strive hard and preserve their prayers, and when Ramadaan finishes, then indeed they abandon the obligatory duties and squander (them). These (people), their striving hard in Ramadaan will not be accepted from them. And it was said to one of the salaf: Indeed, a people strive hard in Ramadaan and when it finishes they abandon the actions. So he said: What an evil people, do they not know Allah except in Ramadaan?! So, these ones, it will not be accepted from them if they abandoned the obligatory duties and abandoned the five (daily) prayers. As for if they abandoned something from the recommended and voluntary acts, then there is no sin upon these, and acceptance is hoped for them for what they did previously in Ramadaan. And Allah knows best.' (Al-Muntaqa Min Fataawa Fadeelatish-Sheikh Saaleh Bin Fawzaan Ibn 'Abdillah Al-Fawzaan, Vol.2, Pp 429-430)

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