Praise be to Allah.
Marriage is one of the means of obtaining provision, as Allaah says (interpretation of the meaning):
“And marry those among you who are single (i.e. a man who has no wife and the woman who has no husband) and (also marry) the Saalihoon (pious, fit and capable ones) of your (male) slaves and maid‑servants (female slaves). If they be poor, Allaah will enrich them out of His Bounty. And Allaah is All‑Sufficient for His creatures’ needs, All‑Knowing (about the state of the people)”
al-Qurtubi (may Allaah have mercy on him) said: “those among you who are single” refers to those who have no spouse, men and women.
And he said: “If they be poor, Allaah will enrich them out of His Bounty” means: do not refrain from getting married because the man or the woman is poor. If they are poor, Allaah will make them independent of means by His bounty. This is a promise of independence of means to those who get married, seeking the pleasure of Allaah and seeking to protect themselves from sin. Ibn Mas’ood said: Seek independence of means through marriage, and he recited this verse. ‘Umar (may Allaah be pleased with him) said: I am surprised by those who do not seek independence of means through marriage, when Allaah has said, “If they be poor, Allaah will enrich them out of His Bounty.” Something similar was also narrated from Ibn ‘Abbaas (may Allaah be pleased with him).
Al-Qurtubi also said: This verse indicates that the poor man should get married, and he should not say, How can I get married when I have no wealth? For his provision comes from Allaah. The Prophet (peace and blessings of Allaah be upon him) gave in marriage a woman who came to offer herself to him, to a man who hadnothing but a single izaar (waist-wrapper). End quote from Tafseer al-Qurtubi (12/218).
And he (peace and blessings of Allaah be upon him) said: “There are three who are all entitled to Allaah’s help: the one who fights for the sake of Allaah; the mukaatab who wants to pay (the price of his freedom); and the one who gets married seeking chastity.” Narrated by al-Tirmidhi (1579), al-Nasaa'i (3166) and Ibn Maajah (2509). This hadeeth was classed as hasan by al-Albaani in Saheeh al-Tirmidhi.
If this young man is going to do the marriage contract, and his wife is going to stay in her father’s house until they can afford to set up home together, there is nothing wrong with that. But he has to look for work so that he can spend on himself, his wife and his house, so that his wife and her family will not be adversely affected if it takes too long.
If what is meant is that his wife will move to his house but they have agreed not to be intimate, so that they will not have children at this stage, that is not appropriate for several reasons:
1-Refraining from intimacy means missing out on something that is one of the most important aims of marriage, which is having children.
2-Refraining from having children for fear of poverty is contrary to putting one’s trust in Allaah, and it is an imitation of the people of Jaahiliyyah who used to kill their children for fear of poverty. Allaah has guaranteed to give provision for every soul, as He says (interpretation of the meaning):
“And no moving (living) creature is there on earth but its provision is due from Allaah. And He knows its dwelling place and its deposit (in the uterus or grave). All is in a Clear Book (Al‑Lauh Al‑Mahfûz — the Book of Decrees with Allaah)”
“And in the heaven is your provision, and that which you are promised”
But we must point out two things:
1 – With regard to marriage, it is essential that the conditions be fulfilled, which is the consent of both parties and that there be no legal impediments such as their being mahrams (relatives to whom marriage is forbidden) or their being related through breastfeeding. The woman’s wali (guardian) and two witnesses must also be present, otherwise the marriage is not valid.
2 – It is not permissible for a man and woman to form a relationship before marriage, because of the many negative consequences to which that will lead, such as falling in love, sickness of the heart (because of sin), looking at one another, being alone together, speaking softly to one another and other things that Allaah has forbidden.
And Allaah knows best.