the Prophet said: "Between every two calls (to prayer) there is a Salat for whoever wills."
Jami` at-Tirmidhi Book 2, Hadith 37
← Previous Hadith "The Prophet only performed the two rak'ah (units of prayer) after Asr because some wealth came to him which distracted him from the two rak'ah after Zuhr, so he prayed them after Asr, then he did not repeat that."

Jami` at-Tirmidhi Book 2, Hadith 36 Next Hadith → the Prophet said: "Whoever catches a Rak'ah of Subh before the sun has risen, then he has caught Subh. Whoever catches a Rak'ah of Asr before the sun has set, then he has caught Asr."

Jami` at-Tirmidhi Book 2, Hadith 38