And the phrase "and give them rope in their trespasses; so they will wander like blind ones [to and fro] (wa yamudduhum fi tughânihim ya'mahûn)" specifies what form [Allâh's] mocking [will take], the punishment for their mockery.

The positioning of the parts of the phrases [and the relationships between them]:

Consider this: the phrase " When they meet those who believe, they say: 'We believe.' Wa idhâ laqû alladhîna âmanû qâlû âmannâ)" denotes their sycophancy.

The certainty expressed by "when (idhâ)" infers definiteness, deliberate-ness, and intention. That is, they deliberately intended to meet the believers.

The verb "they meet (laqû)" indicates that they intended to encounter the believers on thoroughfares in the midst of the people.

The use of the phrase "those who believe (alladhîna âmanû)" in place of 'the believers' (al-mu'minîn) indicates that [the dissemblers] have direct contact with them and that they are in touch with each other, and that the reason for their relations is belief, and that belief is the most outstanding of the believers' attributes.

The word "they say (qâlû)" hints that they say with their mouths what is not in their hearts, and that what they say demonstrates their artificiality, hypocrisy, and sycophancy, and that they say it to rebuff accusations and avidly attract [to themselves] the believers' advantages and so that they might pry into their secrets.

The word "we believe (âmannâ)" not being in the intensive [or corroborative - bilâ ta'kîd) form although the sense requires it, and its being a verbal clause, indicate that there is no passion or incentive in their hearts driving them to be steadfast in what they say. The non-use of the intensive also indicates their strenuous rebuttals of the accusations against them, as though they are saying: "Your denying [our belief] is uncalled for, in fact it's futile, for we're not the sort of people who can be accused." It is also a sign that such vehemence will not give currency to what they say. It also hints that the veil covering their lies and dissembling is so flimsy, if force were applied to it, it would be torn apart. Also, in its being a verbal clause is a sign that they cannot claim to be constant and persistent [in their belief]; their aim in dissimulating while claiming that they have recently come to believe is to share in the believers' benefits and to discover their secrets.