"Stir into flame the gift of God that you have through the imposition of my hands." Most likely this imposition of hands is the ordination of Timothy. Notice the qualifications for leadership that Saint Paul expresses here: Love, self-control, and bearing hardships. This isn't exactly in accordance with what is usually seen by leaders who oppress their people. When things get a little heated, instead of bearing hardships, these dictatorial-type leaders usually demonstrate that spirit of cowardice and flee.
The "gift of God" which Saint Paul writes about is grace. Our Lord supplies us with grace which arms us for what He calls us to do. He supplies the grace to also bear whatever sufferings may come. Perhaps a more fulfilling way to express it is to say that in every moment of this life, grace is sufficient. Unfortunately, fallen humanity doesn't always cooperate with this gift from God. The gift of grace is difficult to understand because it's not something that is concrete or physical; but grace is a gift that is always ready for use. In the case of ordination, grace is, as one anonymous writer puts it, the supernatural fitness received for the worthy exercise of the sacred ministry. And borrowing this definition for a more generic use, it can be said that grace is the supernatural fitness received for the worthy exercise of living a holy life.
The Catechism of the Catholic Church teaches that faith is an entirely free gift from God but we can lose this priceless gift. To live, grow and persevere in faith until the end, we must nourish it with the Word of God (cf.
Why does Jesus use the example of a mustard seed? Saint John Chrysostom explains: "Christ compares faith to a grain of mustard seed because, though the grain is small, it is nevertheless stronger than most herbs." Mulberry trees, once they start dropping berries, are very messy. Life can be messy; there are many things to contend with. In Saint Matthew's Gospel the mulberry tree is replaced with a mountain. A mountain can be translated to mean a large obstacle. "If you have faith the size of a mustard seed," you will never be overwhelmed by any obstacles. If you have faith, then you already know that God's judgment will come as He assures Habakkuk of this in the First Reading. And if you have faith in that, then what must follow is trust in God's time for this to occur.