Be strong in the grace.
Thou therefore, my son, be strong in the grace that is in Christ Jesus. - II Timothy 2:1
from Gill's Exposition of the Entire Bible
Thou therefore, my son,.... "therefore", shows the connection between this and the preceding chapter; "thou, my son", expresses the apostle's tender affection for Timothy, and is the rather used to engage his attention to the advice he was about to give him; which is, that since he had received the true grace of God, and unfeigned faith dwelt in him; and since he had such gifts, qualifying him for the work of the ministry; and since so good a thing as the glorious Gospel of the blessed God was committed to his trust; and since there were so many who had departed from it, and so few that abode by it, he would have him be strong in the grace that is in Christ Jesus...
Romans 8:39 which is in itself always strong, immovable, and unalterable; and is the strength and security of the saints... to be strong in it [grace], is to be rooted and grounded in it, and to have a strong sense and firm persuasion of interest in it, and that nothing can separate from it: ... the Gospel, which is a declaration of grace, and is in Christ, and comes by him... to be strong in [grace], is to preach it boldly, to defend it bravely, and courageously oppose every error and heresy, and every abettor thereof; and it also becomes every private believer to hold it fast, stand fast in it, abide by it, and earnestly contend for it; and so the phrase may stand opposed to , or "one strong in the law", which is so often used by the Jews: or rather by grace is meant the fullness of grace which is in Christ, for the supply of his people; for in that grace which is in him, and not in that which is in themselves, should their dependence be.
Grace in Christ is what believers should always have recourse unto, and exercise faith on; and not only believe that there is such a fullness of grace in Christ...but they should go forth out of themselves unto it, and draw water with joy out of the full wells of salvation in Christ: and this grace is of a strengthening nature... to enable them to fulfill their ministry, to bear reproaches, afflictions, and persecution for the Gospel, and the infirmities of weak brethren; and to private believers, to strengthen them against every corruption, temptation, and snare, to exercise every grace, and discharge every branch of duty.