Du’aa’ is suspended between heaven and earth until you send blessings upon the Prophet (peace and blessings of Allaah be upon him)
Question

                Is this hadeeth saheeh: “Every du’aa’ is suspended until one sends blessings upon the Prophet (peace and blessings of Allaah be upon him)”?.
Praise be to Allah.This hadeeth was narrated 
    by al-Tirmidhi (486) from ‘Umar ibn al-Khattaab (may Allaah be pleased with 
    him) who said: “Du’aa’ is suspended between heaven and earth and none of it 
    is taken up until you send blessings upon your Prophet  (peace and 
    blessings of Allaah be upon him).” Ibn Katheer said: Its isnaad is jayyid. 
    It was classed as hasan by al-Albaani in Saheeh al-Tirmidhi. 
It was narrated by 
    al-Albaani in al-Silsilah al-Saheehah (2035) from the Prophet  
    (peace and blessings of Allaah be upon him), and he mentioned corroborating 
    reports, then he said: “In conclusion, when all these isnaads and 
    corroborating reports are taken into account, the hadeeth is hasan at the 
    very least, in sha Allaah.” 
What was narrated by 
    al-Tirmidhi is mawqoof, with an isnaad ending at ‘Umar, but it is regarded 
    as coming under the heading of marfoo’ (i.e., it may be regarded as 
    attributable to the Prophet  (peace and blessings of Allaah be upon 
    him)). 
Al-Haafiz al-‘Iraaqi 
    said: 
Although this report is 
    mawqoof, such matters cannot be spoken of on the basis of personal opinion 
    (i.e., the Sahaabah did not speak on the basis of personal opinion on 
    matters of worship), rather this is a tawqeefi matter (i.e., we must adhere 
    to what is prescribed in the Qur’aan and Sunnah and not worship Allaah in 
    any way except that which has been prescribed), so it is regarded as coming 
    under the heading of marfoo’ (i.e., it may be regarded as attributable to 
    the Prophet  (peace and blessings of Allaah be upon him)). Al-Qaadi Abu 
    Bakr ibn al-‘Arabi commented, after quoting these words from ‘Umar: ‘Umar 
    would not have said such a thing unless he had heard it from the Prophet 
     (peace and blessings of Allaah be upon him), because this is not a 
    matter that can be worked out by means of human reasoning. 
This hadeeth indicates 
    that it is mustahabb to send blessings upon the Prophet  (peace and 
    blessings of Allaah be upon him) when making du’aa’. 
It seems that this is not 
    a condition of du’aa’, because the Prophet  (peace and blessings of 
    Allaah be upon him) did not do this in all his du’aa’s; rather it may be 
    understood that this is mustahabb. 
And the scholars have 
    stated that three categories of sending blessing upon the Prophet  
    (peace and blessings of Allaah be upon him) when making du’aa’. 
Shaykh Bakr Abu Zayd said 
    in his book Tasheeh al-Du’aa’ (p. 23): 
The best category of 
    sending blessings upon the Prophet  (peace and blessings of Allaah be 
    upon him) is at the beginning of the du’aa’, in the middle and at the end. 
    It is like wings for the du’aa’ with which it soars up to the clouds of the 
    sky. 
The second category is 
    sending blessings upon him at the beginning and end of the du’aa’. 
The third category is 
    sending blessings upon him at the beginning. 
These categories were 
    also mentioned by Ibn al-Qayyim (may Allaah have mercy on him) in his book
    Jala’ al-Afhaam, p. 531-535. 
Al-Tirmidhi (3477) 
    narrated from Fadaalah ibn ‘Ubayd (may Allaah be pleased with him) that the 
    Prophet  (peace and blessings of Allaah be upon him) said: “When any one 
    of you prays, let him begin by praising Allaah, then let him send blessings 
    upon the Prophet  (peace and blessings of Allaah be upon him), then let 
    him ask for whatever he wants.” 
Classed as saheeh by 
    al-Albaani in Saheeh al-Tirmidhi. 
Al-Tabaraani narrated 
    that ‘Abd-Allaah ibn Mas’ood said: If any one of you wants to ask (of 
    Allaah), let him begin by praising Allaah as He deserves to be praised, then 
    let him send blessings upon the Prophet  (peace and blessings of Allaah 
    be upon him), then let him ask after that, for that is more likely to be 
    answered. 
This was quoted by 
    al-Albaani in al-Silsilah al-Saheehah, 3204. 
Abu Sulaymaan al-Daaraani 
    said: Whoever wants to ask Allaah for what he needs, let him start by 
    sending blessings upon the Prophet  (peace and blessings of Allaah be 
    upon him), then ask for what he needs, then end his prayer with blessings 
    upon the Prophet, for his sending blessings upon the Prophet will be 
    accepted, and Allaah is too generous to refuse what comes in between. 
And Allaah knows best.