The truest supplication is the one Allah taught you to make. The Qur'an holds a ready dua for every state — for steadfastness, for patience, for offspring, for forgiveness, for the good of both worlds at once.
Gathered here are the 'Rabbana' and 'Rabbi' supplications in full, each with its surah and verse number and its meaning in plain English — because a dua you understand is not the same as a dua you merely pronounce.
Say them as they are: this is the wording Allah chose for you.
Rabbana la tu'akhidhna in nasina aw akhta'na, Rabbana wa la tahmil 'alayna isran kama hamaltahu 'ala-lladhina min qablina, Rabbana wa la tuhammilna ma la taqata lana bih, wa'fu 'anna waghfir lana warhamna, anta mawlana fansurna 'ala-l-qawmi-l-kafirin.
Our Lord, do not impose blame upon us if we forget or err. Our Lord, lay not upon us a burden like that You laid upon those before us. Our Lord, burden us not with that which we have no ability to bear. And pardon us; and forgive us; and have mercy upon us. You are our protector, so give us victory over the disbelieving people.
Rabbana wa atina ma wa'adtana 'ala rusulika wa la tukhzina yawma-l-qiyamah, innaka la tukhlifu-l-mi'ad.
Our Lord, and grant us what You promised us through Your messengers and do not disgrace us on the Day of Resurrection. Indeed, You do not fail in [Your] promise.
Rabbana wasi'ta kulla shay'in rahmatan wa 'ilman faghfir lilladhina tabu wattaba'u sabilaka wa qihim 'adhaba-l-jahim.
Our Lord, You have encompassed all things in mercy and knowledge, so forgive those who have repented and followed Your way and protect them from the punishment of Hellfire.
Virtue: The supplication of the angels who bear the Throne, for the believers.
Rabbana-ghfir lana wa li-ikhwanina-lladhina sabaquna bil-imani wa la taj'al fi qulubina ghillan lilladhina amanu, Rabbana innaka Ra'ufun Rahim.
Our Lord, forgive us and our brothers who preceded us in faith and put not in our hearts [any] resentment toward those who have believed. Our Lord, indeed You are Kind and Merciful.
'Our Lord, give us good in this world and good in the Hereafter, and protect us from the punishment of the Fire' — the supplication the Prophet ﷺ made most often, gathering both worlds and safety in a single sentence.