Answered by Sayyidi al-Ḥabīb `Umar bin Hafīẓ (may Allāh preserve him and benefit us by him).
How can we remove the desire to outdo our brothers and our envy for them, especially when we see their success in da`wah?
The cure for this is look at the reality. The reality is that nothing happens except by the will of Allāh, so how can we wish for other than what our Lord wills? The reality is that if our brothers succeed in da`wah or in any other realm of the religion, then this is a source of assistance, goodness, blessings and strength for all of us. So how can we dislike this strength, harbour envy towards the one who has been given it and desire for it to be removed? When any one of us increases in faith, succeeds in worshipping Allāh or calling to Him, or in teaching and learning, or purification of the self, then it is a source of strength, blessings and goodness for everyone. We praise Allāh for it, and we desire for many people to be successful in these areas. All the people that work for the sake of the religion are a source of aid for the rest, and a means of collective strength in achieving our goal and purpose in life. Thus we should realise that the success of our brothers is a source of happiness for us, and if we realise this, all feelings of envy will leave us.