Note the key characteristic of true prayer - "in the Holy Spirit." The seed of acceptable devotion must come from heaven's storehouse. Only the prayer that comes from God can go to God. We must shoot the Lord's arrows back to Him. The desire that He writes upon our heart will move His heart and bring down a blessing, but the desires of the flesh have no power with Him.
Praying in the Holy Spirit is praying in fervency. Cold prayers ask the Lord not to hear them. Those who do not plead with fervency do not plead at all. We might as well talk of lukewarm fire as of lukewarm prayer—it is essential that it be red-hot. It is praying perseveringly. The true petitioner gathers force as he proceeds and grows more fervent when God delays to answer. The longer the gate is closed, the louder the knocking becomes; and the longer the angel lingers, the more determined he becomes to never let him go without the blessing. In God's sight tearful, agonizing, unconquerable importunity is commendable. It means praying humbly, for the Holy Spirit never puffs us up with pride. It is His part to convince of sin and to cause us to bow down in contrition and brokenness of spirit.
We will never sing Gloria in excelsis except when we pray to God de profundis: Out of the depths must we cry, or we will never behold glory in the highest. It is loving prayer. Prayer should be perfumed with love, saturated with love—love for our fellow believers and love for Christ. Moreover, it must be a prayer full of faith. A man prevails only to the extent that he believes. The Holy Spirit is the author of faith and strengthens it, so that we pray believing God's promise. Now our prayer is that this blessed combination of excellent graces, as priceless and sweet as rare spices, might be fragrant within us because the Holy Spirit is in our hearts! Blessed Comforter, exert Your mighty power within us, helping our weaknesses in prayer.