"Prayer"
Allah say in the Quran "and your lord say Call upon me and I will respond" (40:30). The prayer is worship. according to Aishah (RA): Prophet Muhammad like short prayer but meaningful and besides it was not his doing. If you pray for other muslim , There is an angel beside your head that will say "Amen".
"Knowledge"
according to Mu'awiyah (RA), Allah's messenger (SAS) say: If Allah like the good deeds and manners of a person, He will give the knowledge in Religion. according to Anas (RA), The prophet (SAS) say: Who teach someone a Knowledge, will be recieve a reward according to the knowledge he\she teach but the person\people who learned will not lost some reward. According to Abdullah bin Amr bin Al-Ass(RA), The prophet (RA) say: You communicate about me, even one verse of the Quran only.
Short Dhikr for Sleeping:
"Bismikallahumma amootu wa ahya"
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