Virtue: On the authority of Abu Dharr (radiAllahu anhu), that the Prophet (sallAllahu alayhi wasallam) said:
“Whoever says ten times immediately after finishing the Fajr (Dawn) Payer, before moving from his place or talking to anyone"
Ten good deeds will be recorded for him, ten sins will be eliminated from him, he will be upgraded ten degrees (in reward), he will be safeguarded from all kinds of harm all that day, he will be guarded against shaytan and no sin can overtake him on that day (and nullify his good deeds) except associating others in worship with Allah.
Likewise it is an act of Sunnah to say dhikr ten times straight after Magrib salah too
Reference: At Tirmidhi #3484