In Psalm 86, the psalmist calls on God for help. He wants the Lord to listen to his prayer and preserve his life. He presents himself as afflicted, poor and faithful to God. Thus, we have here a description of someone who is devoted to God, who considered himself God’s servant, who trusts in God, but who is at this very moment poor, needy and devoid of joy.
In his prayer for help, the psalmist mentions the revelation of God's character in the Book of Exodus as merciful and just (see Ex 34:6-7). Both qualities are evident in God’s way of dealing with His people. He administers justice by letting the people experience the consequences of their wrong choices. But then, He shows mercy to those who acknowledge their iniquities and turns to Him for help. This character of God is described in the well-known parable of the Prodigal Son (see Luke 15:11-32).
The psalmist in his prayer calls on the merciful dimension of God’s character. The Lord should listen to his prayer because, as He revealed to Moses, He is “good and forgiving,
abounding in kindness to all who call upon you” (Ps 86:5). Moreover, the psalmist is persistent in his prayer. By calling to God “all the day”, he reminds us about the persistent widow from one of Jesus’ parables about prayer (see Luke 18:1-5). His persistence is yet another reason to motivate God to action.
What is prayer? Our Catechism defines prayer as “the encounter of God's thirst with ours. God thirsts that we may thirst for him” (CCC, 2560). Then, it continues stating that “our prayer of petition is a response to the plea of the living God” expressed in the Book of Jeremiah: "They have forsaken me, the fountain of living waters, and hewn out cisterns for themselves, broken cisterns that can hold no water!" (Jer 2:13; see CCC, 2561). Here, we find the mystery and paradox of prayer. God, who knows all our needs before we ask him (see Matt 6:8), desires that we come to him with our requests. Prayer is “a response of love to the thirst of the only Son of God” (CCC, 2561).
The psalmist motivates the Lord to hear his plea for help by describing his hopelessness and appealing to God’s mercy. He cannot help himself, but he believes that the Lord can and will help him. He is humble, trusts and persists in his prayer. How about us?