Sayyiduna Rabi'ah al-Jurashi (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) said: "Be upright, and how good it is if you remain upright! Guard your ablution (that is, try to remain always in a state of ablution, or perform complete ablution with care); your best deed is the prayer. And take care of the earth, for it is your origin; whoever does any deed on it, good or bad, it will give news (of that deed)."
Al-Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a narrator, Ibn Lahi'ah, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1242