يَا حَيُّ يَا قَـيُّومُ بِرَحْمَتِكَ أَسْتَغِيثُ
Translation 
O Ever Living, O Self-Subsisting and Supporter of all, by Your Mercy I seek help.
Transliteration
Yaa ḥai yaa qaiyoom bi raḥmatika astagheeth
Sources:
At-Tirmidhi No# 3524
