Imam al-Rida (a.s) is reported as saying, “If one observes fasting on the last three days of Sha`ban and attach it to the obligatory fasting of Ramadan, Almighty Allah will decide his as observing fasting in two consecutive months.”
Abu’l-Salt al-Harawiy has narrated that when he visited Imam al-Rida (a.s) on the last Friday of Sha`ban, the Imam said to him, “Abu’l-Salt: The majority of Sha`ban has passed. This is the last Friday in it. You should thus settle what you have missed in this month by working hard in the rest of it. You may supplicate, seek forgiveness of Almighty Allah, recite the Holy Qur'an, and repent before Almighty Allah from your sins so that you receive the month of Ramadan with pure sincerity to Almighty Allah. You must fulfill all the trusts that you are liable to settle; and do not bear malice against any of your brethren-in-faith; and you must give up any sin that you commit. Fear Almighty Allah and trust in Him in secret and openly, for ‘If any one puts his trust in Allah, sufficient is (Allah) for him. For Allah will surely accomplish his purpose: verily, for all things has Allah appointed a due proportion. 65/3’
In the rest days of Sha`ban, you may repeat the following supplication very much for Almighty Allah saves many people from Hellfire on account of the sanctity of this month:
اللّهُمَّ إنْ لَمْ تَكُنْ غَفَرْتَ لَنَا فِيمَا مَضَى مِنْ شَعْبَانَ
allahumma in lam takun ghafarta lana fima mada min sha`bana
O Allah: If You have not forgiven us in the past days of Sha`ban,
فَاغْفِرْ لَنَا فِيمَا بَقِيَ مِنْهُ.
faghfir lana fima baqiya minhu
(please do) forgive us in the rest of it.
Shaban Thursday - How to end Shaban month
Several narrations were reported which stated that the deeds performed in each month are taken up towards God on its last Thursday.
Thus, it is best for you to try to purify your inner thoughts which are the basis for the approval or lack of approval of your deeds on the last Thursday of Sha'ban since the value of man‟s deeds is based on his intention.
And also try to compensate for the deeds which you have not done and complete them as much as you can and offer them to the Threshold of the Almighty God like one who is afraid of his deeds being rejected.
If we get more happy when we are granted our worldly requests or when we engage in natural worldly lusts of this world compared to what is near the Almighty God, or we get more pleased when our temporary needs are fulfilled compared to when we serve and obey the Almighty God then this is an indication of the deficiency of our deeds. This is a clear sign of an illness and it is improbable for our deeds to be free of problems.
Also pay attention to the fact that you offer your deeds for gaining the reward of the Merciful God to the ones ( Ahlulbayt(as) ) upon whom the deeds of all is offered in the last Thursday of Sha‟ban.
Thus, on the last Thursday of Sha'ban you should offer your deeds to those to whom deeds are offered in order to get rewards from the Merciful God.
You should offer your deeds to them like a guest, a worshipper, a servant who is fleeing from himself and his own temptations, one who seeks refuge in the shadow of his Master‟s justice and grabs unto His Majesty and Benevolence.
You should also offer your deeds with caution in each part of this month in addition to offering them on the last Thursday of this month
Source Iqbal Aamal - Syed ibn tawus