Itlaq presents an expression without an additional restriction relevant to the point, while taqyid adds a qualification that helps delimit the intended referent or claim.
أَكْرِمْ طَالِبًا — Honor a student; no extra descriptive condition is included.
أَكْرِمْ طَالِبًا مُجْتَهِدًا — Honor a diligent student; diligence narrows the description.
If any student is intended, the second expression adds an unwarranted restriction. If the intended meaning is specifically a diligent student, the first does not convey that feature.
These are linguistic illustrations, not claims about substantive legal obligations.