A profound cry of thanksgiving marks a sharp transition from deep distress and darkness into the bright light of salvation. This emotional shift naturally leads to a practical act of gratitude: bringing a thanksgiving offering to the Temple. On a personal level, this reflects the experience of King David, who expresses his deep appreciation for surviving and being cleansed of his suffering following the events involving Bathsheba [רש״י].
God is portrayed as a strong and powerful force who pulls a person out of the dark depths of trouble and into the light of rescue [מאירי, מצודת דוד, ביאור שטיינזלץ]. This light is also understood in a very physical sense. It represents the morning light provided by God, as offerings must be brought during the day rather than at night [אבן עזרא]. Another perspective suggests that the mention of light captures the moment the people went out to greet the king holding bright torches [מלבי״ם].
Following this expression of gratitude comes a call to prepare the sacrifice. The festival offering refers directly to the sacrificial animal itself, as most offerings are brought during the holidays, and the instruction is to bind it securely with thick ropes. This call might be directed from the priests to the Israelites [אבן עזרא], or from the king to the priests [מלבי״ם]. The purpose of these thick ropes is to secure the unblemished animal and prevent it from running wild before it is time for the offering [ביאור שטיינזלץ, מצודת דוד]. An old tradition notes that people would tie these carefully inspected, flawless animals to the legs of their beds until the moment arrived to bring them to the Temple courtyard [רש״י].
The final destination for this bound animal is the altar, specifically the protrusions at its top corners [מצודת ציון]. The animal is led there so that its blood can be applied to these corners, which is the most essential part of the offering process [אבן עזרא, מצודת דוד]. A different tradition offers a completely separate understanding of what is being brought to the altar. Instead of an animal sacrifice, this view suggests the focus is on the long willow branches brought to the Temple during the festival of Sukkot. These branches were so tall that they would lean directly against the corners of the altar [תורה תמימה].