On one occasion, Hazrat Moulana Ashraf Ali Thaanwi (rahmatullahi ‘alaihi) mentioned:

No matter how much a person worships Allah Ta’ala, or adopts taqwa and piety in his life, one cannot feel complacent at any time as one is unaware of one’s true status and position in the sight of Allah Ta’ala. Since everything depends on the acceptance of Allah Ta’ala and His pleasure, who can be bold enough to make any type of claim (regarding his position and status by Allah Ta’ala)? Similarly, no person can be confident of his future (i.e. whether one will pass away with Imaan or not). Since the condition of man’s heart is always changing and fluctuating and one does not know what the future holds for him, how can one feel confident of his future? (Malfoozaat e Hakeemul Ummah 10/33)

Source: Ihyaauddeen.co.za