Sayyiduna Imran bin Husayn (may Allah be pleased with him) says that this saying of the Prophet (peace and blessings be upon him) reached him; he (peace and blessings be upon him) said: "Any one of you continues to be counted as being in prayer as long as the prayer is what holds him back."
Imam al-Tabarani recorded it in al-Mu'jam al-Kabir, and Imam al-Bazzar also recorded it; its chain contains a narrator, Abdullah bin Isa al-Khazzaz, who is da'if (weak). I say: Hadiths have already passed in the chapter on purification about performing ablution thoroughly which indicate the virtue of waiting for the prayer, and some hadiths will come later in the chapter on specification, if Allah wills.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2132