Literally meaning growing larger and deeper spreading and expanding. Sufis use inbisat to signify the relaxing of one's heart to the extent allowed by the Shari'a so that it can embrace everybody and make them pleased or contented with one's gentle words and pleasant manners. In the context of one's relationship with God Almighty it denotes a spiritual state that combines fear and hope. Those who have attained this state are awed by being in the Presence of God and feel exhilarated by the breezes of delight and joy blowing in His Presence. They are awed while inhaling and feel delight when exhaling.
As pointed out in the brief description above expansion can be dealt with in two categories: our relationship with the created and our relationship with the Creator.
With respect to our relationship with the created expansion means that we are careful of our connection with God and the Truth; that we live in our communities as one of its inhabitants being open with and showing respect to everyone; and that we treat people according to their level of understanding.
The noble Prophet upon him be peace and blessings was sincere and frank with those around him and avoided ceremony or formality. He spoke according to his listeners' level of understanding and sometimes made wise and meaningful jokes. Although he suffered inwardly from the unbelief injustice and sins he witnessed and was anxious about everyone's end and afterlife he always smiled and behaved pleasantly. As said in the Minhaj: A heart is like a mirror: too much and too frequent solemnity may cause it to steam up and the only way to remove that steam is to tell pleasant jokes.
With respect to our relationship with God Almighty expansion signifies the simultaneous experiencing of fear and hope in our souls. Being states of the soul fear and hope are usually found in those who have just started to advance on the path to God. Expansion on the other hand is a state of those with knowledge of God and moreover is a dimension of the heart's life. The state resembling the expansion of those still striving to reach this level of expansion is an exhilaration coming from knowledge of God. This may lead them to become relaxed in their relationship with God and thus lose their self-control and self-possession.
Expansion appears when a traveler on the path of God is completely freed from carnal desire and passion and becomes a bright "mirror" to reflect God's Names and Attributes. This station whether called the Station of Combination (where the traveler experiences God's Existence and Unity) or Annihilation (where the traveler's annihilation of self causes forgetfulness of self when in the throes of ecstatic love of God and perception of God's Existence and Unity) is a mysterious point where the traveler directs himself or herself according to the Divine inspirations received and assumes "colors" unknown to everybody else. It is impossible for such people to conceal their expansion while it is insolent of those who have not attained it to talk about it. How aptly Rumi expresses it:
If the king's courtier behaves in an affected manner to attract the king's attention you must not attempt to do so for you do not have the document (to justify your doing so). O one who cannot be freed from the restrictions of this transient life how can you know what (the stations of) annihilation drunkenness and expansion mean?
Indeed servants of the body cannot be aware of the states of the spirit. It is impossible for those imprisoned in the body to be aware of spirituality. We should ask those souls who have burned and been "roasted" many times in the fire of the love of God about the pains of a heart that has been cleft open and their expansion and contraction.