When any of the Companions met with his brother, he would ask him to pray for him, especially if he were traveling to the holiest place on earth: the blessed city of Mecca. Muslim and Abū Dāwūd reported that Safwān bnu ‘Abdillāh bnu Safwān bnu Umayya bnu Khalaf, the husband of ad-Dardā’, said:
“When I came to ash-Shām (present-day Palestine, Lebanon , Jordan and Syria), I went to Abū ad-Dardā’s house. I did not find him but found his wife, Um ad-Dardā’. She said, ‘Do you intend to perform Pilgrimage this year?’ I said, Yes. She said, ‘Then pray for me, for God’s Messenger (God bless him and give him peace) used to say, ‘The Muslim’s prayers for his brother in his absence are answered. Standing by him is a commissioned angel who tells him whenever he prays for his brother: Amen! And your reward—the prayers you asked for him—shall be the same.’ I went to the market and met Abū ad-Dardā’. He told me the same Ḥadīth, which he reported on the authority of the Prophet (God bless him and give him peace).
At-Tirmidhī, Ibn Māja, and Abū Dāwūd reported that ‘Umar bnu al-Khattāb (God be pleased with him) asked permission to perform ‘Umra (lesser pilgrimage) from God’s Messenger (God bless him and give him peace), who told him : “O brother, include me in your prayers and do not forget me.”
Ibn Ḥibbān in his Ṣaḥīḥ, and al-Bazzār in his Musnad, reported that ‘Āisha (God be pleased with her) said:
“When I saw God’s Messenger (God bless him and give him peace) in a good mood, I told him: O Messenger of God! Pray to God for me! He said, ‘O Lord! Forgive ‘Āisha all her sins, past and future, inward and outward.’ Āisha kept laughing until her head fell into her laps. God’s Messenger (God bless him and give him peace) told her, ‘Has my invocation pleased you?’ She said, ‘And how could it not?’ He (God bless him and give him peace) told her, ‘That is the invocation I pray to God for my Umma in every Ritual Prayer.’”