How does one get rid of the feeling of envy when seeing others do good deeds, especially in matters of worship, so that one may have a sound heart?

The praiseworthy feeling of jealousy in acts of obedience is ghibṭah (envy without wishing ill upon others), which does not involve wishing for the removal of blessings from others. However, the most complete state is for the heart to be free from comparison and competition with others, as was the case with Abu Bakr Al-Siddiq and Abu Ubaidah ibn Al-Jarrah, may Allah be pleased with them, for they had none of that. What helps in achieving this is remembering that Allah is the Giver, and that encouragement combined with praiseworthy jealousy is not hypocrisy; rather, it is a call to Allah and an urging towards good.