In Sahih Muslim 389 a, it says “When Satan hears the call to prayer, he turns back and breaks the wind so as not to hear the call being made” 

And the prophet also mentioned “the place where the the adhan is proclaimed is blessed by Allah and it remains immune to torments and calamities” (Al-Tabarani)

The saying, hayya alal falah is just one part of the adhan. The meaning of this phrase is “hasten to success” or “rush to success”.

hayya alal falah meaning:

So when you hear the adhan hayya alal falah remember that you are being called upon to come and pray salah. Your success is in your Salah, not your job.

In Surah Al-Jumu’ah ayah 11 it says, “But when they saw a transaction or a diversion, [O Muhammad], they rushed to it and left you standing. Say, “What is with Allah is better than diversion and than a transaction, and Allah is the best of providers.”

Remember the saying “If you follow what is easy your life will be hard, but if you do what is hard your life will be easy.”

What’s easy to do is ignore the call to prayer and to continue on the task your currently engaged in. What is hard is to leave what you were doing and to “hasten to success” meaning come to prayer.

HAYYA ALAL FALAH in Arabic:

In Arabic this is written, 

  حي على الفلاح

If you hear the Mu’adhin either say hayya alal falah or hayya alas salah the response or reply according to hadith should be:

لا حَوْلَ وَلا قُوَّةَ إِلا بِالله

la hawla wala quwwata illa billah
There is no might nor power except with Allah. [1]

By saying these words you are in agreement with what the Mu’adhin had just said which again is, hayya alas salah (come to salah) and hayya alal falah (hasten to success).

We are helpless without Allah subhanu wa ta’ala only with him will we able to do good and abstain from evil.

According to Imam Malik, when someone hears these words he recommends the listener to just repeat the words of the Mu’adhin.

Reference:

[1] Sahih Muslim 385  – Umar b. al-Khattab reported: The Messenger of Allah (ﷺ) said: When the Mu’adhdhin says: Allah is the Greatest, Allah is the Greatest, and one of you should make this response: Allah is the Greatest, Allah is the Greatest; (and when the Mu’adhdhin) says: I testify that there is no god but Allah, one should respond: I testify that there is no god but Allah, and when he says: I testify that Muhammad is the Messenger of Allah, one should make a response: I testify that Muhammad is Allah’s Messenger. When he (the Mu’adhdhin) says: Come to prayer, one should make a response: There is no might and no power except with Allah. When he (the Mu’adhdhin) says: Come to salvation, one should respond: There is no might and no power except with Allah, and when he (the Mu’adhdhin) says: Allah is the Greatest, Allah is the Greatest, then make a response: Allah is the Greatest, Allah is the Greatest. When he (the Mu’adhdhin) says: There is no god but Allah, and he who makes a re- sponse from the heart: There is no god but Allah, he will enter Paradise.