First off, I'd like to refer to a Quranic statement about praying, that is prayer in general which is called du'a, and not just the formal compulsory prayer (salaah) which it is obligatory to perform at five specific time intervals during the day.

(It's weird that one has to use his hands in this forum to avail himself of HTML. For this and other reasons, this forum seems to have a rather primitive design. But the content is more important than the form anyway.)




To learn the English translation of the above Quranic statement, see 40-65 in a Quran translation.

If you want to pray for whatever believers you may have offended, you can offer this prayer that the Messenger of Allah (peace be upon him) himself offered as reported in the hadeeth collections of Imam Muslim and Imam Ahmad ibn Hanbal:



There are a lot of prayers that are reported to have been offered by Muhammad, our Prophet (peace be upon him) when he was sad. Of course, it's also a good idea for us to offer them when we are sad. Here is just one of them which is reported in the hadeeth collections of Imams al-Bukhari and Muslim:



I have mentioned a few of the prayers of our Prophet (peace be upon him). However, we shouldn't forget that to say our prayers in our own words is also very important. This better proves that we are sincerely praying and not just unconsciously reciting some words that we have memorized somehow.