Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) once mentioned:

There is no stagnation in deen. One is either progressing or retrogressing. If a person does not strive and make effort in deen, his spiritual condition will gradually begin to weaken. To understand this concept, consider the example of a garden. When the water and air are favourable, the lushness and fertility of the garden improves. However, when the weather is unfavourable and the water insufficient, you do not find the previous lushness and fertility remaining. Rather, the condition of the garden immediately begins to deteriorate. Similar is the condition of one’s deen. (Malfoozaat Hazrat Moulana Muhammad Ilyaas (rahmatullahi ‘alaih) pg. 80)

Source: Ihyaauddeen.co.za