Hawzah News Agency – The merciful prophet of Islam (pbuh) says:

لا علَيكُم أنْ تُعْجَبوا بأحَدٍ حتّى‏ تَنْظُروا بما يُخْتَمُ لَهُ، فإنَّ العامِلَ يَعْمَلُ زَماناً مِن عُمرِهِ أو بُرْهَةً مِن دَهْرِهِ بعَمَلٍ صالحٍ لو ماتَ علَيهِ دَخَلَ الجَنّةَ، ثُمَّ يَتَحَوّلُ فيَعْمَلُ عَمَلاً سَيّئاً.

'Do not be amazed by [the good actions of] anyone until you see his end, for verily one may perform good actions for a period of his life that if he were to die during that time he would enter Paradise, but he subsequently changes and then commits evil actions.'

Source: Kanz al-Ummal, no. 589