Isaiah 55:6 Seek ye the LORD while he may be found, call ye upon him while he is near:
Barnes:
That the time will come when it will be impossible to obtain his favor.The leading thought is, that under the Messiah the offer of salvation will be made to people fully and freely. But the period will come when it will be withdrawn.
if they neglect or despise the provisions of mercy and die in their sins, it will be too late, and mercy cannot then be found.
How unspeakably important, then, is it to seek for mercy at once – lest, slighted now, the offer should be withdrawn. or lest death should overtake us, and we be removed to a world where mercy is unknown!
How important is the present moment – for another moment may place us beyond the reach of pardon and of grace!
How amazing the stupidity of men who suffer their present moments to pass away unimproved, and who, amidst the gaieties and the business of life, permit the day of salvation to pass by, and lose their souls!
And how just is the condemnation of the sinner! If a man will not do so simple a thing as to ask for pardon, he ought to perish. The universe will approve the condemnation of such a man; and the voice of complaint can never be raised against that Holy Being who consigns such a sinner to hell.
Call ye upon him – That is, implore his mercy (see Romans 10:13; compare Joel 2:32).
How easy are the terms of salvation!
How just will be the condemnation of a sinner if he will not call upon God!
Assuredly, if people will not breathe out one broken-hearted petition to the God of heaven that they may be saved, they have only to blame themselves if they are lost. The terms of salvation could be made no easier; and man can ask nothing more simple.
While he is near – In an important sense God is equally near to us at all times. But this figurative language is taken from the mode of speaking among people, and it denotes that there are influences more favorable for seeking him at some periods than others.
Thus God comes near to us in the preaching of his word, when it is borne with power to the conscience;
in his providences, when he strikes down a friend and comes into the very circle where we move, or the very dwelling where we abide;
when he lays his hand upon us in sickness, he is near us by day and by night;
in a revival of religion, or
when a pious friend pleads with us, God is near to us then, and is calling us to his favor.
These are favorable times for salvation; times which, if they are suffered to pass by unimproved, return no more; periods which will all soon be gone, and when they are gone, the sinner irrecoverably dies.
Proverbs 27:1 Boast not thyself of to morrow; for thou knowest not what a day may bring forth.
2 Corinthians 6:2 (For he saith, I have heard thee in a time accepted, and in the day of salvation have I succoured thee: behold, now is the accepted time; behold, now is the day of salvation.)
Hebrews 2:3 How shall we escape, if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us by them that heard him;
Luke 19:41-44 And when he was come near, he beheld the city, and wept over it, Saying, If thou hadst known, even thou, at least in this thy day, the things which belong unto thy peace! but now they are hid from thine eyes. For the days shall come upon thee, that thine enemies shall cast a trench about thee, and compass thee round, and keep thee in on every side, And shall lay thee even with the ground, and thy children within thee; and they shall not leave in thee one stone upon another; because thou knewest not the time of thy visitation.