It is narrated from Hazrat Amr bin Abasah (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Whoever builds a mosque for the pleasure of Allah so that Allah's name may be remembered in it, Allah will build a house for him in Paradise. And whoever frees a Muslim slave, for every limb of that slave, it will become a means of his freedom from Hell. And whoever grows old in the way of Allah, that old age will be a source of light for him on the Day of Judgment.
Hadith Referenceمسند احمد / تتمہ مُسْنَدِ الْكُوفِيِّينَ / 19440
Hadith Gradingحکم دارالسلام:حديث صحيح دون قوله: من بنى لله مسجدا... فصحيح لغيره، وهذا إسناد ضعيف، فيه بقية بن الوليد، وهو مدلس يدلس تدليس التسوية