Ruling on putting prayers together and shortening them when not travelling

Praise
be to Allah.

Firstly: 

Not paying at all constitutes kufr (disbelief) that puts one beyond the pale
of Islam, according to the correct scholarly opinion. For more information,
please see the answer to question no. 5208. 

With regard to the person who prays sometimes and does not pray at other
times some of the scholars are of the view that he is also a kaafir
(disbeliever), which is the view narrated from a number of the Sahaabah, and
is also the view cited in fatwas of the Standing Committee for Issuing
Fatwas which was headed by Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allah have
mercy on him). 

Other scholars are of the view that he does not become a kaafir unless he
does not pray at all, such as Shaykh al-Islam Ibn Taymiyah (may Allah have
mercy on him) and Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him). For
more information, please see the answers to questions no.
52923 and 83165. 

Secondly: 

The scholars differed concerning the one who deliberately does not pray
(such as one who is too lazy to pray, and the like): does he have to make up
the prayers, as is required of one who sleeps and misses a prayer or one who
forgets, and is it in fact more appropriate that the one who does not pray
without any excuse should be instructed to make up the prayer, rather than
the one who do have an excuse, as is the view of the majority of scholars,
and the four madhhabs and others are agreed on this point? 

Or
is it the case that he does not have to do that, and if he does make them up
it will not benefit him, either because not praying constitutes kufr and the
prayer of the disbeliever does not benefit him so long as he remains a
disbeliever, and he is not instructed to make up what he missed during the
time when he was a disbeliever and apostate; or because every act of worship
is connected to a particular time, and if a person does not do it at the
proper time with no legitimate excuse, it will not be accepted from him,
because the Prophet (blessings and peace of Allah be upon him) said:
“Whoever does an action that is not part of this matter of ours will have it
rejected” (narrated by Muslim, 1718)? For more information, please see the
answers to questions no. 105849 and
197247 

The ruling on shortening the prayer when not travelling is no different from
the ruling on not praying at all. If a person offers a prayer but omits one
rak‘ah or prostration, or he omits one of its pillars or essential parts
deliberately, his prayer is invalidated and he is like one who did not pray
it at all. He is closer to toying with the rituals, and such a person is in
grave danger, if Allah does not bestow His mercy upon him and bless him by
enabling him to repent sincerely. 

It
was narrated that Ibn ‘Abbaas said: Allah enjoined the prayer on the lips of
your Prophet (blessings and peace of Allah be upon him); four rak‘ahs when
not travelling, two rak‘ahs when travelling, and one rak‘ah at times of
fear. Narrated by Muslim (687). 

Ibn Hazm (may Allah have mercy on him) said: The number of rak‘ahs does not
change (when travelling) except in the case of Zuhr, ‘Asr and ‘Isha’: they
are four rak‘ahs when not travelling, for both healthy and sick individuals,
two rak‘ahs when travelling and one rak‘ah at times of fear. There is
scholarly consensus on all of that, except with regard to whether these
prayers may be offered with one rak‘ah at times of fear – there is a
difference of opinion concerning that.

End quote from al-Muhalla (3/185) 

Fourthly:

 it is not permissible to put two prayers together without an excuse; if a
person puts prayers together without any excuse or legitimate justification
for doing so, then he is sinning, because he is going against the shar‘i
texts that regulate the prayer, such as the verse in which Allah, may He be
exalted, says (interpretation of the meaning): “Verily,
the prayer is enjoined on the believers at fixed hours”
[an-Nisa’ 4:103]. 

Another such text is the hadith in which the Prophet (blessings and peace of
Allah be upon him) said: “Jibreel (peace be upon him) led me in prayer at
the Ka‘bah twice. He led me in praying Zuhr when the sun had passed the
meridian and the shadow was the length of a sandal-strap; then he led me in
praying ‘Asr when the (length of a thing’s) shadow was equal to its height;
then he led me in praying Maghrib at the time when the fasting person breaks
his fast; then he led me in praying ‘Isha’ at the time when the red
afterglow had disappeared; then he led me in praying Fajr at the time when
food and drink become prohibited to the one who is fasting. Then the next
day he led me in praying Zuhr when the (length of a thing’s) shadow was
equal to its height; then he led me in praying ‘Asr when the (length of a
thing’s) shadow was equal to twice its height; then he led me in praying
Maghrib at the time when the fasting person breaks his fast; then he led me
in praying ‘Isha’ when one third of the night had passed; then he led me in
praying Fajr when it had grown light. Then he turned to me and said: O
Muhammad, these are the times at which the Prophets before you prayed, the
time is between each of these two times (for each prayer).”

Narrated by Abu Dawood (393) and at-Tirmidhi (149). Al-Albaani said: Its
isnaad is hasan saheeh, in Saheeh Abi Dawood – al-Umm, no. 417 

Ibn Qudaamah (may Allah have mercy on him) said: The Muslims are unanimously
agreed that the five daily prayers are to be offered at certain times which
are well-known and strictly defined, and several saheeh hadiths have been
narrated concerning that.

End quote from al-Mughni (1/224) 

Once this is established, it is not permissible to put two prayers together
unless there is a reason to doing so, such as travel, rain, or sickness. If
there is no reason for putting prayers together, then you should abide by
the original timings for the prayers

See: al-Mughni by Ibn Qudaamah
(2/60) 

Shaykh Ibn ‘Uthaymeen (may Allah have
mercy on him) said: Because the Prophet (blessings and peace of Allah be
upon him) defined the timings of the prayer in detail, doing the prayer at
any other time constitutes transgressing the limits set by Allah.
“And
whoever transgresses the limits ordained by Allah, then such are the
Zalimoon (wrong-doers)”
[al-Baqarah 2:229].
Whoever offers a prayer before its time, knowingly and deliberately, is
sinning and has to repeat it, but if he did not do that knowingly and
deliberately, then he is not sinning, but he does have to repeat it. This
applies to putting two prayers together at the time of the earlier prayer
with no legitimate reason; the prayer that was brought forward is not
valid and he has to repeat it. 

If a person delays a prayer until after
its time, knowingly and deliberately, with no excuse, he is sinning and
his prayer is not accepted, according to the more correct scholarly
opinion. This applies to putting two prayers together at the time of the
later prayer with no legitimate reason. The prayer that was delayed will
not be accepted, according to the more correct scholarly opinion. 

The Muslim has to fear Allah, may He be
exalted, and not be careless with regard to this extremely important
matter.

End quote from Majmoo‘ al-Fataawa
(15/387) 

What you must do now is repent to Allah
sincerely from what you have done, and mend your ways in the future. You
have to make yourself respect the issue of prayer, which is the greatest
duty that Allah requires of His slaves. 

If you err on the side of caution and
try hard to make up the prayers that you missed, especially those which
you shortened or put together when you were not travelling, with no
legitimate excuse, that will be better for you and is more likely to
ensure that you have discharged your obligations. 

You should also do a lot of
supererogatory actions, as much as you can, especially supererogatory (naafil)
prayers. Allah, may He be exalted, says (interpretation of the meaning):

“And
perform As-Salat (Iqamat-as-Salat), at the two ends of the day and in some
hours of the night (i.e. the five compulsory Salat (prayers)). Verily, the
good deeds remove the evil deeds (i.e. small sins). That is a reminder (an
advice) for the mindful (those who accept advice).

And be patient; verily, Allah loses
not the reward of the good-doers”

[Hood 11:114-115]. 

And Allah knows best.